Organic electroluminescent materials and devices

ABSTRACT

Compounds containing indolocarbazole and terphenyl building blocks are disclosed in this application. These compounds are useful for application in organic electroluminescent devices.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 15/283,982, filed Oct. 3, 2016, which is a continuation-in-partof U.S. patent application Ser. No. 15/064,023, filed Mar. 8, 2016,which claims priority from U.S. Provisional Patent Application Ser. Nos.62/143,370, filed Apr. 6, 2015, 62/245,578, filed Oct. 23, 2015,62/254,299, filed Nov. 12, 2015, and 62/274,520, filed Jan. 4, 2016, allof which applications are incorporated by reference herein in theirentireties.

PARTIES TO A JOINT RESEARCH AGREEMENT

The claimed invention was made by, on behalf of, and/or in connectionwith one or more of the following parties to a joint universitycorporation research agreement: Regents of the University of Michigan,Princeton University, University of Southern California, and theUniversal Display Corporation. The agreement was in effect on and beforethe date the claimed invention was made, and the claimed invention wasmade as a result of activities undertaken within the scope of theagreement.

FIELD OF THE INVENTION

The present invention relates to compounds for use as host materials orelectron transporting materials, and devices, such as organic lightemitting diodes, including the same.

BACKGROUND

Opto-electronic devices that make use of organic materials are becomingincreasingly desirable for a number of reasons. Many of the materialsused to make such devices are relatively inexpensive, so organicopto-electronic devices have the potential for cost advantages overinorganic devices. In addition, the inherent properties of organicmaterials, such as their flexibility, may make them well suited forparticular applications such as fabrication on a flexible substrate.Examples of organic opto-electronic devices include organic lightemitting diodes/devices (OLEDs), organic phototransistors, organicphotovoltaic cells, and organic photodetectors. For OLEDs, the organicmaterials may have performance advantages over conventional materials.For example, the wavelength at which an organic emissive layer emitslight may generally be readily tuned with appropriate dopants.

OLEDs make use of thin organic films that emit light when voltage isapplied across the device. OLEDs are becoming an increasinglyinteresting technology for use in applications such as flat paneldisplays, illumination, and backlighting. Several OLED materials andconfigurations are described in U.S. Pat. Nos. 5,844,363, 6,303,238, and5,707,745, which are incorporated herein by reference in their entirety.

One application for phosphorescent emissive molecules is a full colordisplay. Industry standards for such a display call for pixels adaptedto emit particular colors, referred to as “saturated” colors. Inparticular, these standards call for saturated red, green, and bluepixels. Alternatively the OLED can be designed to emit white light. Inconventional liquid crystal displays emission from a white backlight isfiltered using absorption filters to produce red, green and blueemission. The same technique can also be used with OLEDs. The white OLEDcan be either a single EML device or a stack structure. Color may bemeasured using CIE coordinates, which are well known to the art.

One example of a green emissive molecule is tris(2-phenylpyridine)iridium, denoted Ir(ppy)₃, which has the following structure:

In this, and later figures herein, we depict the dative bond fromnitrogen to metal (here, Ir) as a straight line.

As used herein, the term “organic” includes polymeric materials as wellas small molecule organic materials that may be used to fabricateorganic opto-electronic devices. “Small molecule” refers to any organicmaterial that is not a polymer, and “small molecules” may actually bequite large. Small molecules may include repeat units in somecircumstances. For example, using a long chain alkyl group as asubstituent does not remove a molecule from the “small molecule” class.Small molecules may also be incorporated into polymers, for example as apendent group on a polymer backbone or as a part of the backbone. Smallmolecules may also serve as the core moiety of a dendrimer, whichconsists of a series of chemical shells built on the core moiety. Thecore moiety of a dendrimer may be a fluorescent or phosphorescent smallmolecule emitter. A dendrimer may be a “small molecule,” and it isbelieved that all dendrimers currently used in the field of OLEDs aresmall molecules.

As used herein, “top” means furthest away from the substrate, while“bottom” means closest to the substrate. Where a first layer isdescribed as “disposed over” a second layer, the first layer is disposedfurther away from substrate. There may be other layers between the firstand second layer, unless it is specified that the first layer is “incontact with” the second layer. For example, a cathode may be describedas “disposed over” an anode, even though there are various organiclayers in between.

As used herein, “solution processible” means capable of being dissolved,dispersed, or transported in and/or deposited from a liquid medium,either in solution or suspension form.

A ligand may be referred to as “photoactive” when it is believed thatthe ligand directly contributes to the photoactive properties of anemissive material. A ligand may be referred to as “ancillary” when it isbelieved that the ligand does not contribute to the photoactiveproperties of an emissive material, although an ancillary ligand mayalter the properties of a photoactive ligand.

As used herein, and as would be generally understood by one skilled inthe art, a first “Highest Occupied Molecular Orbital” (HOMO) or “LowestUnoccupied Molecular Orbital” (LUMO) energy level is “greater than” or“higher than” a second HOMO or LUMO energy level if the first energylevel is closer to the vacuum energy level. Since ionization potentials(IP) are measured as a negative energy relative to a vacuum level, ahigher HOMO energy level corresponds to an IP having a smaller absolutevalue (an IP that is less negative). Similarly, a higher LUMO energylevel corresponds to an electron affinity (EA) having a smaller absolutevalue (an EA that is less negative). On a conventional energy leveldiagram, with the vacuum level at the top, the LUMO energy level of amaterial is higher than the HOMO energy level of the same material. A“higher” HOMO or LUMO energy level appears closer to the top of such adiagram than a “lower” HOMO or LUMO energy level.

As used herein, and as would be generally understood by one skilled inthe art, a first work function is “greater than” or “higher than” asecond work function if the first work function has a higher absolutevalue. Because work functions are generally measured as negative numbersrelative to vacuum level, this means that a “higher” work function ismore negative. On a conventional energy level diagram, with the vacuumlevel at the top, a “higher” work function is illustrated as furtheraway from the vacuum level in the downward direction. Thus, thedefinitions of HOMO and LUMO energy levels follow a different conventionthan work functions.

More details on OLEDs, and the definitions described above, can be foundin U.S. Pat. No. 7,279,704, which is incorporated herein by reference inits entirety.

Indolocarbazole and oligophenylenes have excellent charge-transportproperties, useful for organic electronic devices. Thus, there is a needin the art for novel indolocarbazole, oligophenylenes, andindolocarbazole-oligophenylenes to be used in organic electronicdevices.

SUMMARY

According to an embodiment, a composition of materials is providedcomprising a first compound, wherein the first compound has a formulaselected from the group consisting of Formula I and Formula II:

wherein R is selected from the group consisting of:

wherein R⁴ is selected from the group consisting of alkyl, alkoxy,silyl, aryl, heteroaryl, and combinations thereof;

wherein R¹, R² and R³ each independently represents mono to maximumallowable substitutions, or no substitution;

wherein R¹, R² and R³ are each independently selected from the groupconsisting of hydrogen, deuterium, alkyl, alkenyl, alkyne, alkoxy,halogen, silyl, nitrile, nitro, aryl, heteroaryl and combinationsthereof;

wherein any two adjacent substituents are optionally joined or fusedinto a ring;

wherein R⁴, R¹, R², and R³ are each independently, optionally, furthersubstituted with one or more substituents selected from the groupconsisting of hydrogen, deuterium, alkyl, alkenyl, alkyne, alkoxy,halogen, silyl, nitrile, nitro, aryl, heteroaryl, and combinationsthereof; and

wherein any hydrogen in the compound is optionally replaced withdeuterium.

According to another embodiment, an organic light emitting diode/device(OLED) is also provided. The OLED can include an anode, a cathode, andan organic layer, disposed between the anode and the cathode. Theorganic layer can include a composition of materials comprising a firstcompound, wherein the first compound has a formula selected from thegroup consisting of Formula I and Formula II. According to yet anotherembodiment, the organic light emitting device is incorporated into adevice selected from a consumer product, an electronic component module,and/or a lighting panel.

According to another embodiment, a consumer product comprising anorganic light-emitting device (OLED) is provided. The OLED can includean anode, a cathode, and an organic layer, disposed between the anodeand the cathode. The organic layer can include a composition ofmaterials comprising a first compound, wherein the first compound has aformula selected from the group consisting of Formula I and Formula II.

According to another embodiment, an emissive region or an emissive layeris provided. The emissive region or emissive layer can include acomposition of materials comprising a first compound, wherein the firstcompound has a formula selected from the group consisting of Formula Iand Formula II.

According to another embodiment, the invention provides a method forfabricating an organic light emitting device comprising a firstelectrode, a second electrode, and a first organic layer disposedbetween the first electrode and the second electrode, wherein the firstorganic layer comprises a first composition comprising a mixture of afirst compound and a second compound, wherein the first compound has aformula selected from the group consisting of Formula I and Formula II,and the second compound has the Formula III.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an organic light emitting device.

FIG. 2 shows an inverted organic light emitting device that does nothave a separate electron transport layer.

DETAILED DESCRIPTION

Generally, an OLED comprises at least one organic layer disposed betweenand electrically connected to an anode and a cathode. When a current isapplied, the anode injects holes and the cathode injects electrons intothe organic layer(s). The injected holes and electrons each migratetoward the oppositely charged electrode. When an electron and holelocalize on the same molecule, an “exciton,” which is a localizedelectron-hole pair having an excited energy state, is formed. Light isemitted when the exciton relaxes via a photoemissive mechanism. In somecases, the exciton may be localized on an excimer or an exciplex.Non-radiative mechanisms, such as thermal relaxation, may also occur,but are generally considered undesirable.

The initial OLEDs used emissive molecules that emitted light from theirsinglet states (“fluorescence”) as disclosed, for example, in U.S. Pat.No. 4,769,292, which is incorporated by reference in its entirety.Fluorescent emission generally occurs in a time frame of less than 10nanoseconds.

More recently, OLEDs having emissive materials that emit light fromtriplet states (“phosphorescence”) have been demonstrated. Baldo et al.,“Highly Efficient Phosphorescent Emission from OrganicElectroluminescent Devices.” Nature, vol. 395, 151-154, 1998;(“Baldo-I”) and Baldo et al., “Very high-efficiency green organiclight-emitting devices based on electrophosphorescence,” Appl. Phys.Lett., vol. 75, No. 3, 4-6 (1999) (“Baldo-II”), are incorporated byreference in their entireties. Phosphorescence is described in moredetail in U.S. Pat. No. 7,279,704 at cols. 5-6, which are incorporatedby reference.

FIG. 1 shows an organic light emitting device 100. The figures are notnecessarily drawn to scale. Device 100 may include a substrate 110, ananode 115, a hole injection layer 120, a hole transport layer 125, anelectron blocking layer 130, an emissive layer 135, a hole blockinglayer 140, an electron transport layer 145, an electron injection layer150, a protective layer 155, a cathode 160, and a barrier layer 170.Cathode 160 is a compound cathode having a first conductive layer 162and a second conductive layer 164. Device 100 may be fabricated bydepositing the layers described, in order. The properties and functionsof these various layers, as well as example materials, are described inmore detail in U.S. Pat. No. 7,279,704 at cols. 6-10, which areincorporated by reference.

More examples for each of these layers are available. For example, aflexible and transparent substrate-anode combination is disclosed inU.S. Pat. No. 5,844,363, which is incorporated by reference in itsentirety. An example of a p-doped hole transport layer is m-MTDATA dopedwith F₄-TCNQ at a molar ratio of 50:1, as disclosed in U.S. PatentApplication Publication No. 2003/0230980, which is incorporated byreference in its entirety. Examples of emissive and host materials aredisclosed in U.S. Pat. No. 6,303,238 to Thompson et al., which isincorporated by reference in its entirety. An example of an n-dopedelectron transport layer is BPhen doped with Li at a molar ratio of 1:1,as disclosed in U.S. Patent Application Publication No. 2003/0230980,which is incorporated by reference in its entirety. U.S. Pat. Nos.5,703,436 and 5,707,745, which are incorporated by reference in theirentireties, disclose examples of cathodes including compound cathodeshaving a thin layer of metal such as Mg:Ag with an overlyingtransparent, electrically-conductive, sputter-deposited ITO layer. Thetheory and use of blocking layers is described in more detail in U.S.Pat. No. 6,097,147 and U.S. Patent Application Publication No.2003/0230980, which are incorporated by reference in their entireties.Examples of injection layers are provided in U.S. Patent ApplicationPublication No. 2004/0174116, which is incorporated by reference in itsentirety. A description of protective layers may be found in U.S. PatentApplication Publication No. 2004/0174116, which is incorporated byreference in its entirety.

FIG. 2 shows an inverted OLED 200. The device includes a substrate 210,a cathode 215, an emissive layer 220, a hole transport layer 225, and ananode 230. Device 200 may be fabricated by depositing the layersdescribed, in order. Because the most common OLED configuration has acathode disposed over the anode, and device 200 has cathode 215 disposedunder anode 230, device 200 may be referred to as an “inverted” OLED.Materials similar to those described with respect to device 100 may beused in the corresponding layers of device 200. FIG. 2 provides oneexample of how some layers may be omitted from the structure of device100.

The simple layered structure illustrated in FIGS. 1 and 2 is provided byway of non-limiting example, and it is understood that embodiments ofthe invention may be used in connection with a wide variety of otherstructures. The specific materials and structures described areexemplary in nature, and other materials and structures may be used.Functional OLEDs may be achieved by combining the various layersdescribed in different ways, or layers may be omitted entirely, based ondesign, performance, and cost factors. Other layers not specificallydescribed may also be included. Materials other than those specificallydescribed may be used. Although many of the examples provided hereindescribe various layers as comprising a single material, it isunderstood that combinations of materials, such as a mixture of host anddopant, or more generally a mixture, may be used. Also, the layers mayhave various sublayers. The names given to the various layers herein arenot intended to be strictly limiting. For example, in device 200, holetransport layer 225 transports holes and injects holes into emissivelayer 220, and may be described as a hole transport layer or a holeinjection layer. In one embodiment, an OLED may be described as havingan “organic layer” disposed between a cathode and an anode. This organiclayer may comprise a single layer, or may further comprise multiplelayers of different organic materials as described, for example, withrespect to FIGS. 1 and 2.

Structures and materials not specifically described may also be used,such as OLEDs comprised of polymeric materials (PLEDs) such as disclosedin U.S. Pat. No. 5,247,190 to Friend et al., which is incorporated byreference in its entirety. By way of further example, OLEDs having asingle organic layer may be used. OLEDs may be stacked, for example asdescribed in U.S. Pat. No. 5,707,745 to Forrest et al, which isincorporated by reference in its entirety. The OLED structure maydeviate from the simple layered structure illustrated in FIGS. 1 and 2.For example, the substrate may include an angled reflective surface toimprove out-coupling, such as a mesa structure as described in U.S. Pat.No. 6,091,195 to Forrest et al., and/or a pit structure as described inU.S. Pat. No. 5,834,893 to Bulovic et al., which are incorporated byreference in their entireties.

Unless otherwise specified, any of the layers of the various embodimentsmay be deposited by any suitable method. For the organic layers,preferred methods include thermal evaporation, ink-jet, such asdescribed in U.S. Pat. Nos. 6,013,982 and 6,087,196, which areincorporated by reference in their entireties, organic vapor phasedeposition (OVPD), such as described in U.S. Pat. No. 6,337,102 toForrest et al., which is incorporated by reference in its entirety, anddeposition by organic vapor jet printing (OVJP), such as described inU.S. Pat. No. 7,431,968, which is incorporated by reference in itsentirety. Other suitable deposition methods include spin coating andother solution based processes. Solution based processes are preferablycarried out in nitrogen or an inert atmosphere. For the other layers,preferred methods include thermal evaporation. Preferred patterningmethods include deposition through a mask, cold welding such asdescribed in U.S. Pat. Nos. 6,294,398 and 6,468,819, which areincorporated by reference in their entireties, and patterning associatedwith some of the deposition methods such as ink-jet and OVJD. Othermethods may also be used. The materials to be deposited may be modifiedto make them compatible with a particular deposition method. Forexample, substituents such as alkyl and aryl groups, branched orunbranched, and preferably containing at least 3 carbons, may be used insmall molecules to enhance their ability to undergo solution processing.Substituents having 20 carbons or more may be used, and 3-20 carbons isa preferred range. Materials with asymmetric structures may have bettersolution processability than those having symmetric structures, becauseasymmetric materials may have a lower tendency to recrystallize.Dendrimer substituents may be used to enhance the ability of smallmolecules to undergo solution processing.

Devices fabricated in accordance with embodiments of the presentinvention may further optionally comprise a barrier layer. One purposeof the barrier layer is to protect the electrodes and organic layersfrom damaging exposure to harmful species in the environment includingmoisture, vapor and/or gases, etc. The barrier layer may be depositedover, under or next to a substrate, an electrode, or over any otherparts of a device including an edge. The barrier layer may comprise asingle layer, or multiple layers. The barrier layer may be formed byvarious known chemical vapor deposition techniques and may includecompositions having a single phase as well as compositions havingmultiple phases. Any suitable material or combination of materials maybe used for the barrier layer. The barrier layer may incorporate aninorganic or an organic compound or both. The preferred barrier layercomprises a mixture of a polymeric material and a non-polymeric materialas described in U.S. Pat. No. 7,968,146, PCT Pat. Application Nos.PCT/US2007/023098 and PCT/US2009/042829, which are herein incorporatedby reference in their entireties. To be considered a “mixture”, theaforesaid polymeric and non-polymeric materials comprising the barrierlayer should be deposited under the same reaction conditions and/or atthe same time. The weight ratio of polymeric to non-polymeric materialmay be in the range of 95:5 to 5:95. The polymeric material and thenon-polymeric material may be created from the same precursor material.In one example, the mixture of a polymeric material and a non-polymericmaterial consists essentially of polymeric silicon and inorganicsilicon.

Devices fabricated in accordance with embodiments of the invention canbe incorporated into a wide variety of electronic component modules (orunits) that can be incorporated into a variety of electronic products orintermediate components. Examples of such electronic products orintermediate components include display screens, lighting devices suchas discrete light source devices or lighting panels, etc. that can beutilized by the end-user product manufacturers. Such electroniccomponent modules can optionally include the driving electronics and/orpower source(s). Devices fabricated in accordance with embodiments ofthe invention can be incorporated into a wide variety of consumerproducts that have one or more of the electronic component modules (orunits) incorporated therein. A consumer product comprising an OLED thatincludes the compound of the present disclosure in the organic layer inthe OLED is disclosed. Such consumer products would include any kind ofproducts that include one or more light source(s) and/or one or more ofsome type of visual displays. Some examples of such consumer productsinclude flat panel displays, curved displays, computer monitors, medicalmonitors, televisions, billboards, lights for interior or exteriorillumination and/or signaling, heads-up displays, fully or partiallytransparent displays, flexible displays, rollable displays, foldabledisplays, stretchable displays, laser printers, telephones, mobilephones, tablets, phablets, personal digital assistants (PDAs), wearabledevices, laptop computers, digital cameras, camcorders, viewfinders,micro-displays (displays that are less than 2 inches diagonal), 3-Ddisplays, virtual reality or augmented reality displays, vehicles, videowalls comprising multiple displays tiled together, theater or stadiumscreen, and a sign. Various control mechanisms may be used to controldevices fabricated in accordance with the present invention, includingpassive matrix and active matrix. Many of the devices are intended foruse in a temperature range comfortable to humans, such as 18 degrees C.to 30 degrees C., and more preferably at room temperature (20-25 degreesC.), but could be used outside this temperature range, for example, from−40 degree C. to +80 degree C.

The materials and structures described herein may have applications indevices other than OLEDs. For example, other optoelectronic devices suchas organic solar cells and organic photodetectors may employ thematerials and structures. More generally, organic devices, such asorganic transistors, may employ the materials and structures.

The term “halo,” “halogen,” or “halide” as used herein includesfluorine, chlorine, bromine, and iodine.

The term “alkyl” as used herein contemplates both straight and branchedchain alkyl radicals. Preferred alkyl groups are those containing fromone to fifteen carbon atoms and includes methyl, ethyl, propyl,I-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, pentyl,1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl,1,2-dimethylpropyl, 2,2-dimethylpropyl, and the like. Additionally, thealkyl group may be optionally substituted.

The term “cycloalkyl” as used herein contemplates cyclic alkyl radicals.Preferred cycloalkyl groups are those containing 3 to 10 ring carbonatoms and includes cyclopropyl, cyclopentyl, cyclohexyl, adamantyl, andthe like. Additionally, the cycloalkyl group may be optionallysubstituted.

The term “alkenyl” as used herein contemplates both straight andbranched chain alkene radicals. Preferred alkenyl groups are thosecontaining two to fifteen carbon atoms. Additionally, the alkenyl groupmay be optionally substituted.

The term “alkynyl” as used herein contemplates both straight andbranched chain alkyne radicals. Preferred alkynyl groups are thosecontaining two to fifteen carbon atoms. Additionally, the alkynyl groupmay be optionally substituted.

The terms “aralkyl” or “arylalkyl” as used herein are usedinterchangeably and contemplate an alkyl group that has as a substituentan aromatic group. Additionally, the aralkyl group may be optionallysubstituted.

The term “heterocyclic group” as used herein contemplates aromatic andnon-aromatic cyclic radicals. Hetero-aromatic cyclic radicals also meansheteroaryl. Preferred hetero-non-aromatic cyclic groups are thosecontaining 3 to 7 ring atoms which includes at least one hetero atom,and includes cyclic amines such as morpholino, piperidino, pyrrolidino,and the like, and cyclic ethers, such as tetrahydrofuran,tetrahydropyran, and the like. Additionally, the heterocyclic group maybe optionally substituted.

The term “aryl” or “aromatic group” as used herein contemplatessingle-ring groups and polycyclic ring systems. The polycyclic rings mayhave two or more rings in which two carbons are common to two adjoiningrings (the rings are “fused”) wherein at least one of the rings isaromatic, e.g., the other rings can be cycloalkyls, cycloalkenyls, aryl,heterocycles, and/or heteroaryls. Preferred aryl groups are thosecontaining six to thirty carbon atoms, preferably six to twenty carbonatoms, more preferably six to twelve carbon atoms. Especially preferredis an aryl group having six carbons, ten carbons or twelve carbons.Suitable aryl groups include phenyl, biphenyl, triphenyl, triphenylene,tetraphenylene, naphthalene, anthracene, phenalene, phenanthrene,fluorene, pyrene, chrysene, perylene, and azulene, preferably phenyl,biphenyl, triphenyl, triphenylene, fluorene, and naphthalene.Additionally, the aryl group may be optionally substituted.

The term “heteroaryl” as used herein contemplates single-ringhetero-aromatic groups that may include from one to five heteroatoms.The term heteroaryl also includes polycyclic hetero-aromatic systemshaving two or more rings in which two atoms are common to two adjoiningrings (the rings are “fused”) wherein at least one of the rings is aheteroaryl, e.g., the other rings can be cycloalkyls, cycloalkenyls,aryl, heterocycles, and/or heteroaryls. Preferred heteroaryl groups arethose containing three to thirty carbon atoms, preferably three totwenty carbon atoms, more preferably three to twelve carbon atoms.Suitable heteroaryl groups include dibenzothiophene, dibenzofuran,dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene,benzoselenophene, carbazole, indolocarbazole, pyridylindole,pyrrolodipyridine, pyrazole, imidazole, triazole, oxazole, thiazole,oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine,pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine,indole, benzimidazole, indazole, indoxazine, benzoxazole, benzisoxazole,benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline,quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine,phenazine, phenothiazine, phenoxazine, benzofuropyridine,furodipyridine, benzothienopyridine, thienodipyridine,benzoselenophenopyridine, and selenophenodipyridine, preferablydibenzothiophene, dibenzofuran, dibenzoselenophene, carbazole,indolocarbazole, imidazole, pyridine, triazine, benzimidazole,1,2-azaborine, 1,3-azaborine, 1,4-azaborine, borazine, and aza-analogsthereof and aza-analogs thereof. Additionally, the heteroaryl group maybe optionally substituted.

The alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl, heterocyclic group,aryl, and heteroaryl may be unsubstituted or may be substituted with oneor more substituents selected from the group consisting of deuterium,halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy,amino, cyclic amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ether,ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof.

As used herein, “substituted” indicates that a substituent other than His bonded to the relevant position, such as carbon. Thus, for example,where R¹ is mono-substituted, then one R¹ must be other than H.Similarly, where R¹ is di-substituted, then two of R¹ must be other thanH. Similarly, where R¹ is unsubstituted, R¹ is hydrogen for allavailable positions.

The “aza” designation in the fragments described herein, i.e.aza-dibenzofuran, aza-dibenzothiophene, etc. means that one or more ofthe C—H groups in the respective fragment can be replaced by a nitrogenatom, for example, and without any limitation, azatriphenyleneencompasses both dibenzo[f,h]quinoxaline and dibenzo[f,h]quinoline. Oneof ordinary skill in the art can readily envision other nitrogen analogsof the aza-derivatives described above, and all such analogs areintended to be encompassed by the terms as set forth herein.

It is to be understood that when a molecular fragment is described asbeing a substituent or otherwise attached to another moiety, its namemay be written as if it were a fragment (e.g. phenyl, phenylene,naphthyl, dibenzofuryl) or as if it were the whole molecule (e.g.benzene, naphthalene, dibenzofuran). As used herein, these differentways of designating a substituent or attached fragment are considered tobe equivalent.

Both indolocarbazole and oligophenylenes have excellent charge-transportproperties, useful for organic electronic devices. According to thisinvention, selected indolocarbazoles with favorable HOMO/LUMO energylevels and high triplet energy are combined with terphenyl to createnovel compounds demonstrating superior performance in OLEDs. Furtherderivatization on these compounds provides additional advantages forthis class of compounds.

Often, the emissive layer (EML) of OLED devices exhibiting good lifetimeand efficiency requires more than two components (e.g. 3 or 4components). Fabricating such EMLs using vacuum thermal evaporation(VTE) process then requires evaporating 3 or 4 evaporation sourcematerials in separate VTE sublimation crucibles, which is verycomplicated and costly compared to a standard two-component EML with asingle host and an emitter, which requires only two evaporation sources.

Premixing two or more materials and evaporating them from one VTEsublimation crucible can reduce the complexity of the fabricationprocess. However, the co-evaporation must be stable and produce anevaporated film having a composition that remains constant through theevaporation process. Variations in the film's composition may adverselyaffect the device performance. In order to obtain a stableco-evaporation from a mixture of compounds under vacuum, it may beassumed that the materials must have the same evaporation temperatureunder the same condition. However, this may not be the only parameterone has to consider. When two compounds are mixed together, they mayinteract with each other and the evaporation property of the mixture maydiffer from their individual properties. On the other hand, materialswith slightly different evaporation temperatures may form a stableco-evaporation mixture. Therefore, it is extremely difficult to achievea stable co-evaporation mixture. So far, there have been very few stableco-evaporation mixture examples. “Evaporation temperature” of a materialis measured in a vacuum deposition tool at a constant pressure, normallybetween 1×10⁻⁷ Torr to 1×10⁻⁸ Torr, at a 2 Å/sec deposition rate on asurface positioned at a set distance away from the evaporation source ofthe material being evaporated, e.g. sublimation crucible in a VTE tool.The various measured values such as temperature, pressure, depositionrate, etc. disclosed herein are expected to have nominal variationsbecause of the expected tolerances in the measurements that producedthese quantitative values as understood by one of ordinary skill in theart.

Many factors other than temperature can contribute to the ability toachieve stable co-evaporation, such as the miscibility of the differentmaterials and the phase transition temperatures of the differentmaterials. In one aspect of the invention, it was found that when twomaterials have similar evaporation temperatures, and similar mass lossrate or similar vapor pressures, the two materials can co-evaporateconsistently. “Mass loss rate” of a material is defined as thepercentage of mass lost over time (“percentage/minute” or “%/min”) andis determined by measuring the time it takes to lose the first 10% ofthe mass of a sample of the material as measured by thermal gravityanalysis (TGA) under a given experimental condition at a given constanttemperature for a given material after a steady evaporation state isreached. The given constant temperature is one temperature point that ischosen so that the value of mass loss rate is between about 0.05 to0.50% d/min. A skilled person in this field should appreciate that inorder to compare two parameters, the experimental condition should beconsistent. The method of measuring mass loss rate and vapor pressure iswell known in the art and can be found, for example, in Bull. et al.Mater. Sci. 2011, 34, 7, which is incorporated herein by reference inits entirety.

In the state of the art OLED devices, the EML may consist of three ormore components. In one example, the EML can consist of two host-typecompounds and an emitter combination (e.g. a hole transporting cohost(h-host), an electron transporting cohost (e-host), and a compoundcapable of functioning as an emitter in an OLED at room temperature). Inanother example, the EML can consist of one host-type compound and twoemitter-type compounds (e.g., a host compound and two compounds eachcapable of functioning as an emitter in an OLED at room temperature).Conventionally, in order to fabricate such EMLs having three or morecomponents using VTE process, three or more evaporation sources arerequired, one for each of the components. Because the concentration ofthe components is important for the device performance, typically, therate of deposition of each component is measured individually during thedeposition process. This makes the VTE process complicated and costly.Thus, it is desired to premix at least two of the components of suchEMLs to reduce the number of VTE evaporation sources.

If any two of the three or more components of the EMLs can be premixedand form a stable mixture of co-evaporation source, then the number ofevaporation sources required for EML layer fabrication would be reduced.In order for materials to be premixable into an evaporation source, theyshould co-evaporate and deposit uniformly without changing the ratio.The ratio of the components in the mixture should be the same as theratio of the components in the evaporation deposited films from thesepremixed materials. Therefore, the concentration of the two componentsin the deposited film is controlled by their concentration in thepremixed evaporation source.

Compounds of the Invention

The compounds of the present invention may be synthesized usingtechniques well-known in the art of organic synthesis. The startingmaterials and intermediates required for the synthesis may be obtainedfrom commercial sources or synthesized according to methods known tothose skilled in the art.

In one aspect, the invention relates to a compound having a formulaselected from the group consisting of:

wherein R is selected from the group consisting of:

wherein R⁴ is selected from the group consisting of alkyl, alkoxy,silyl, aryl, heteroaryl, and combinations thereof;

wherein R¹, R² and R³ each independently represents mono to maximumallowable substitutions, or no substitution;

wherein R¹, R² and R³ are each independently selected from the groupconsisting of hydrogen, deuterium, alkyl, alkenyl, alkyne, alkoxy,halogen, silyl, nitrile, nitro, aryl, heteroaryl and combinationsthereof;

wherein any two adjacent substituents are optionally joined or fusedinto a ring;

wherein R⁴, R¹, R², and R³ are each independently, optionally, furthersubstituted with one or more substituents selected from the groupconsisting of hydrogen, deuterium, alkyl, alkenyl, alkyne, alkoxy,halogen, silyl, nitrile, nitro, aryl, heteroaryl, and combinationsthereof; and

wherein any hydrogen in the compound is optionally replaced withdeuterium.

In one embodiment, the formula is Formula I. In another embodiment, theformula is Formula II. In another embodiment, R¹, R² and R³ are each ahydrogen.

In one embodiment, R⁴ is selected from the group consisting of

and combinations thereof.

wherein X is selected from a group consisting of O, S and Se.

In another aspect, the invention relates to a compound selected from thegroup consisting of:

In another aspect, the present invention includes a composition ofmaterials comprising a first compound, wherein the first compound has aformula selected from the group consisting of Formula I and Formula II.

In one embodiment, the composition comprises a second compound, whereinthe second compound is selected from the group consisting of:

wherein G¹ is selected from the group consisting of dibenzofuran,dibenzothiophene, dibenzoselenophene, triphenylene, and fluorene;

wherein L¹, L², and L³ are each independently selected from the groupconsisting of a direct bond, phenyl, biphenyl, terphenyl, pyridine,pyrimidine, and combinations thereof;

wherein G⁴ is selected from the group consisting of phenyl, biphenyl,terphenyl, naphthalene, phenanthrene, triphenylene, pyridine,pyrimidine, pyrazine, quinoline, isoquinoline, phenanthroline, andcombinations thereof;

wherein G², G³, and G⁵ are each independently selected from the groupconsisting of phenyl, biphenyl, terphenyl, fluorene, naphthalene,phenanthrene, pyridine, pyrimidine, pyrazine, quinoline, isoquinoline,phenanthroline, aza-fluorene, carbazole, and combinations thereof;

wherein G¹, G², G³, G⁴, and G⁵ are each optionally further substitutedwith one or more unfused substituents selected from the group consistingof deuterium, alkyl, alkoxyl, cycloalkyl, cycloalkoxyl, halogen, nitro,nitrile, silyl, phenyl, biphenyl, terphenyl, pyridine, and combinationsthereof;

wherein m is an integer from 0 to 7,

wherein n is an integer from 0 to 4;

wherein, when m or n is larger than 1, each G⁴ or G⁵ can be the same ordifferent:

wherein when n is 0, then m is equal to or greater than 1, and each G⁴is selected from the group consisting of phenyl and biphenyl:

wherein when n is equal to or greater than 1, L¹ is not a direct bond;and

wherein when m and n are both 0, L¹ is biphenyl; and

wherein L⁴ and L⁵ are each independently selected from the groupconsisting of a direct bond, phenyl, biphenyl, terphenyl, pyridine,pyrimidine, and combinations thereof;

wherein R⁵, R⁶, and R⁷ each represent mono to the maximum allowablesubstitution, or no substitution;

wherein R⁸ and R⁹ are each independently a substituted or unsubstitutedaryl or heteroaryl group;

wherein at least one of R⁸ and R⁹ is selected from the group consistingof:

wherein R¹⁰ represents mono to the maximum allowable substitution, or nosubstitution;

wherein R³, R⁶, R⁷, R¹⁰, and R¹¹ are each independently selected fromthe group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl,heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl,carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl,sulfonyl, phosphino, and combinations thereof; and

wherein any two substituents may be joined or fused together to form aring.

In one embodiment, each R⁵, R⁶, R⁷, R¹⁰, and R¹¹ is independentlyselected from the group consisting of hydrogen, deuterium, fluorine,alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, andcombinations thereof.

In one embodiment, G², G³ and G⁵ are independently selected from thegroup consisting of:

wherein R^(B1) and R^(B2) are independently selected from a groupconsisting of hydrogen, deuterium, alkyl, alkenyl, cycloalkyl, alkoxyl,aryl, heteraryl, halogen, and combinations thereof; and

wherein R^(B1) and R^(B2) are optionally joined to form a ring.

In one embodiment, R⁸ and R⁹ are independently selected from the groupconsisting of:

In one embodiment, L⁴ is a direct bond, and L⁵ is a phenyl ring.

In one embodiment, at least one of R⁸ or R⁹ is

wherein A² and A³ are each independently selected from the groupconsisting of hydrogen, phenyl, biphenyl, terphenyl, naphthalene, andcombinations thereof.

In one embodiment, L⁴ and R⁸ are fused together to form a ring. In oneembodiment, L⁵ and R⁹ are fused together to form a ring.

In one embodiment, the second compound has the formula:

wherein X is selected from the group consisting of O, S and Se:

wherein A¹ represents mono to the maximum allowable substitution, or nosubstitution; and

wherein each A¹, A², and A³ is independently selected from the groupconsisting of hydrogen, phenyl, biphenyl, terphenyl, naphthalene, andcombinations thereof.

In one embodiment, the second compound is selected from the groupconsisting of:

Compound G1

Compound G2

Compound G3

Compound G4

Compound G5

Compound G6

Compound G7

Compound G8

Compound G9

Compound G10

Compound G11

Compound G12

Compound G13

Compound G14

Compound G15

Compound G16

Compound G17

Compound G18

Compound G19

Compound G20

Compound G21

Compound G22

Compound G23

Compound G24

Compound G25

Compound G26

Compound G27

Compound G28

Compound G29

Compound G30

Compound G31

Compound G32

Compound G33

Compound G34

Compound G35

Compound G36

In one embodiment, the first compound is Formula I.

In one embodiment, the first compound has an evaporation temperature T1of 150 to 350° C.;

wherein the second compound has an evaporation temperature T2 of 150 to350° C.;

wherein the absolute value of T1−T2 is less than 20° C.:

wherein the first compound has a concentration C1 in said mixture and aconcentration C2 in a film formed by evaporating the mixture in a vacuumdeposition tool at a constant pressure between 1×10 Torr to 1×10⁻⁹ Torr,at a 2 Å/sec deposition rate on a surface positioned at a predefineddistance away from the mixture being evaporated; and

wherein the absolute value of (C1−C2)/C1 is less than 5%.

In one embodiment, the first compound has evaporation temperature T1 of200 to 350° C. and the second compound has evaporation temperature T2 of200 to 350° C.

In one embodiment, the absolute value of (C1−C2)/C1 is less than 3%.

In one embodiment, the first compound has a vapor pressure of P1 at T1at 1 atm, the second compound has a vapor pressure of P2 at T2 at 1 atm;and

wherein the ratio of P1/P2 is within the range of 0.90 to 1.10.

In one embodiment, the first compound has a first mass loss rate and thesecond compound has a second mass loss rate, wherein the ratio betweenthe first mass loss rate and the second mass loss rate is within therange of 0.90 to 1.10. In another embodiment, the first compound has afirst mass loss rate and the second compound has a second mass lossrate, wherein the ratio between the first mass loss rate and the secondmass loss rate is within the range of 0.95 to 1.05. In anotherembodiment, the first compound has a first mass loss rate and the secondcompound has a second mass loss rate, wherein the ratio between thefirst mass loss rate and the second mass loss rate is within the rangeof 0.97 to 1.03.

In one embodiment, the first compound and the second compound each has apurity in excess of 99% as determined by high pressure liquidchromatography.

In one embodiment, the composition further comprises a third compound,wherein the third compound has a different chemical structure than thefirst and second compounds, wherein the third compound has anevaporation temperature T3 of 150 to 350° C., and wherein absolute valueof T1−T3 is less than 20° C.

In one embodiment, the composition further comprises a third compound,wherein the third compound has a different chemical structure than thefirst and second compounds, wherein the third compound has a third massloss rate and the ratio between the first mass loss rate and third massloss rate is within the range of 0.90 to 1.10

In one embodiment, the composition is in liquid form at a temperatureless than T1 and T2.

In some embodiments, the compound can be an emissive dopant. In someembodiments, the compound can produce emissions via phosphorescence,fluorescence, thermally activated delayed fluorescence, i.e., TADF (alsoreferred to as E-type delayed fluorescence), triplet-tripletannihilation, or combinations of these processes.

Devices of the Invention

According to another aspect of the present disclosure, an OLED is alsoprovided. The OLED includes an anode, a cathode, and an organic layerdisposed between the anode and the cathode. The organic layer mayinclude a host and a phosphorescent dopant. The organic layer caninclude a compound having a formula selected from the group consistingof Formula I and Formula II, and their variations as described herein.The organic layer can also include a composition of materials comprisinga first compound, wherein the first compound has a formula selected fromthe group consisting of Formula I and Formula II.

In some embodiments, the OLED has one or more characteristics selectedfrom the group consisting of being flexible, being rollable, beingfoldable, being stretchable, and being curved. In some embodiments, theOLED is transparent or semi-transparent. In some embodiments, the OLEDfurther comprises a layer comprising carbon nanotubes.

In some embodiments, the OLED further comprises a layer comprising adelayed fluorescent emitter. In some embodiments, the OLED comprises aRGB pixel arrangement or white plus color filter pixel arrangement. Insome embodiments, the OLED is a mobile device, a hand held device, or awearable device. In some embodiments, the OLED is a display panel havingless than 10 inch diagonal or 50 square inch area. In some embodiments,the OLED is a display panel having at least 10 inch diagonal or 50square inch area. In some embodiments, the OLED is a lighting panel.

In some embodiments, the present invention relates to an emissive regionor an emissive layer. The emissive region or emissive layer can includea compound of the present invention. In one embodiment, the compound ofthe present invention is a host.

The organic layer can also include an emissive dopant. In someembodiments, two or more emissive dopants are preferred. In someembodiments of the emissive region, the emissive region furthercomprises a phosphorescent emissive dopant. In one embodiment, theemissive dopant is a transition metal complex having at least one ligandor part of the ligand if the ligand is more than bidentate selected fromthe group consisting of:

wherein each Y¹ to Y¹³ are independently selected from the groupconsisting of carbon and nitrogen;

wherein Y′ is selected from the group consisting of BR_(e), NR_(e),PR_(e), O, S, Se, C═O, S═O, SO₂, CR_(e)R_(f)RR, SiR_(e)R_(f), andGeR_(e)R_(f);

wherein R_(e) and R_(f) are optionally fused or joined to form a ring;

wherein each R_(a), R_(b), R_(c), and R_(d) may independently representfrom mono substitution to the maximum possible number of substitution,or no substitution;

wherein each R_(a), R_(b), R_(c), R_(d), R_(e), and R_(f) isindependently selected from the group consisting of hydrogen, deuterium,halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy,amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile,isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinationsthereof; and

wherein any two adjacent substituents of R_(a), R_(b), R_(c), and R_(d)are optionally fused or joined to form a ring or form a multidentateligand.

Additional information on possible emissive dopants is provided below.

The OLED disclosed herein can be incorporated into one or more of aconsumer product, an electronic component module, and a lighting panel.

In one embodiment, the consumer product is selected from the groupconsisting of a flat panel display, a curved display, a computermonitor, a medical monitor, a television, a billboard, a light forinterior or exterior illumination and/or signaling, a heads-up display,a fully or partially transparent display, a flexible display, a rollabledisplay, a foldable display, a stretchable display, a laser printer, atelephone, a cell phone, tablet, a phablet, a personal digital assistant(PDA), a wearable device, a laptop computer, a digital camera, acamcorder, a viewfinder, a micro-display that is less than 2 inchesdiagonal, a 3-D display, a virtual reality or augmented reality display,a vehicle, a video walls comprising multiple displays tiled together, atheater or stadium screen, and a sign.

In one embodiment, the organic layer is an emissive layer and thecompound of Formula I or Formula II is a host. In some embodiments theorganic layer is a blocking layer and the compound of Formula I orFormula II is a blocking material in the organic layer. In otherembodiments the organic layer is a transporting layer and the compoundof Formula I or Formula II is a transporting material in the organiclayer

In some embodiments, the organic layer further comprises aphosphorescent emissive dopant. In one embodiment, the emissive dopantis a transition metal complex having at least one ligand or part of theligand if the ligand is more than bidentate selected from the groupconsisting of:

wherein each Y¹ to Y¹³ are independently selected from the groupconsisting of carbon and nitrogen;

wherein Y′ is selected from the group consisting of BR_(e), NR_(e),PR_(e), O, S, Se, C═O, S═O, SO₂, CR_(e)R_(f)RR, SiR_(e)R_(f), andGeR_(e)R_(f);

wherein R_(e) and R_(f) are optionally fused or joined to form a ring;

wherein each R_(a), R_(b), R_(c), and R_(d) may independently representfrom mono substitution to the maximum possible number of substitution,or no substitution;

wherein each R_(a), R_(b), R_(c), R_(d), R_(e), and R_(f) isindependently selected from the group consisting of hydrogen, deuterium,halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy,amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile,isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinationsthereof; and

wherein any two adjacent substituents of R_(a), R_(b), R_(c), and R_(d)are optionally fused or joined to form a ring or form a multidentateligand.

In one embodiment, each R_(a), R_(b), R_(c), R_(d), R_(e), and R_(f) isindependently selected from the group consisting of hydrogen, deuterium,fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl,alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile,isonitrile, and combinations thereof.

According to another aspect, a formulation comprising a composition ofmaterials comprising a first compound described herein is alsodisclosed.

The emitter dopants can be phosphorescent dopants and/or fluorescentdopants. The organic layer can include a composition of materialscomprising a first compound, wherein the first compound has a formulaselected from the group consisting of Formula I and Formula II and itsvariations as described herein as a host.

In yet another aspect of the present disclosure, a formulation thatcomprises the novel compound disclosed herein is described. Theformulation can include one or more components selected from the groupconsisting of a solvent, a host, a hole injection material, holetransport material, and an electron transport layer material, disclosedherein.

In yet another aspect of the present disclosure, a method forfabricating an organic light emitting device comprising a firstelectrode, a second electrode, and a first organic layer disposedbetween the first electrode and the second electrode is also described,wherein the first organic layer comprises a first composition comprisinga mixture of a first compound and a second compound, wherein the firstcompound has a formula selected from the group consisting of Formula Iand Formula II, and wherein the second compound has the Formula III. Themethod may include the steps of providing a substrate having the firstelectrode disposed thereon, depositing the first composition over thefirst electrode, and depositing the second electrode over the firstorganic layer.

In yet another aspect of the present disclosure, a formulation thatcomprises a compound according to Formula I or Formula II is described.The formulation can include one or more components selected from thegroup consisting of a solvent, a host, a hole injection material, holetransport material, and an electron transport layer material, disclosedherein.

Combination with Other Materials

The materials described herein as useful for a particular layer in anorganic light emitting device may be used in combination with a widevariety of other materials present in the device. For example, emissivedopants disclosed herein may be used in conjunction with a wide varietyof hosts, transport layers, blocking layers, injection layers,electrodes and other layers that may be present. The materials describedor referred to below are non-limiting examples of materials that may beuseful in combination with the compounds disclosed herein, and one ofskill in the art can readily consult the literature to identify othermaterials that may be useful in combination.

Conductivity Dopants:

A charge transport layer can be doped with conductivity dopants tosubstantially alter its density of charge carriers, which will in turnalter its conductivity. The conductivity is increased by generatingcharge carriers in the matrix material, and depending on the type ofdopant, a change in the Fermi level of the semiconductor may also beachieved. Hole-transporting layer can be doped by p-type conductivitydopants and n-type conductivity dopants are used in theelectron-transporting layer. Non-limiting examples of the conductivitydopants that may be used in an OLED in combination with materialsdisclosed herein are exemplified below together with references thatdisclose those materials: EP01617493, EP01968131, EP2020694, EP2684932,US20050139810, US20070160905, US20090167167, US2010288362, WO06081780,WO2009003455, WO2009008277, WO2009011327, WO2014009310, US2007252140.US2015060804 and US2012146012.

HIL/HTL:

A hole injecting/transporting material to be used in the presentinvention is not particularly limited, and any compound may be used aslong as the compound is typically used as a hole injecting/transportingmaterial. Examples of the material include, but are not limited to: aphthalocyanine or porphyrin derivative; an aromatic amine derivative; anindolocarbazole derivative; a polymer containing fluorohydrocarbon; apolymer with conductivity dopants; a conducting polymer, such asPEDOT/PSS; a self-assembly monomer derived from compounds such asphosphonic acid and silyl derivatives; a metal oxide derivative, such asMoO_(x); a p-type semiconducting organic compound, such as1,4,5,8,9,12-Hexaazatriphenylenehexacarbcmitrile; a metal complex, and across-linkable compounds.

Examples of aromatic amine derivatives used in HIL or HTL include, butare not limited to the following general structures:

Each of Ar¹ to Ar⁹ is selected from the group consisting of aromatichydrocarbon cyclic compounds such as benzene, biphenyl, triphenyl,triphenylene, naphthalene, anthracene, phenalene, phenanthrene,fluorene, pyrene, chrysene, perylene, and azulene; the group consistingof aromatic heterocyclic compounds such as dibenzothiophene,dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran,benzothiophene, benzoselenophene, carbazole, indolocarbazole,pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole,oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole,pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine,oxathiazine, oxadiazine, indole, benzimidazole, indazole, indoxazine,benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline,cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine,pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine,benzofuropyridine, furodipyridine, benzothienopyridine,thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine;and the group consisting of 2 to 10 cyclic structural units which aregroups of the same type or different types selected from the aromatichydrocarbon cyclic group and the aromatic heterocyclic group and arebonded to each other directly or via at least one of oxygen atom,nitrogen atom, sulfur atom, silicon atom, phosphorus atom, boron atom,chain structural unit and the aliphatic cyclic group. Each Ar may beunsubstituted or may be substituted by a substituent selected from thegroup consisting of deuterium, halide, alkyl, cycloalkyl, heteroalkyl,arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylicacids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl,phosphino, and combinations thereof.

In one aspect. Ar¹ to Ar⁹ is independently selected from the groupconsisting of:

wherein k is an integer from 1 to 20; X¹⁰⁸ to X¹⁰⁸ is C (including CH)or N; Z¹⁰¹ is NAr¹, O, or S; Ar¹ has the same group defined above.

Examples of metal complexes used in HIL or HTL include, but are notlimited to the following general formula:

wherein Met is a metal, which can have an atomic weight greater than 40;(Y¹⁰¹-Y¹⁰²) is a bidentate ligand, Y¹⁰¹ and Y¹⁰² are independentlyselected from C, N, O, P, and S; L¹⁰¹ is an ancillary ligand; k′ is aninteger value from 1 to the maximum number of ligands that may beattached to the metal; and k′+k″ is the maximum number of ligands thatmay be attached to the metal.

In one aspect, (Y¹⁰¹-Y¹⁰²) is a 2-phenylpyridine derivative. In anotheraspect, (Y¹⁰¹-Y¹⁰) is a carbene ligand. In another aspect, Met isselected from Ir, Pt, Os, and Zn. In a further aspect, the metal complexhas a smallest oxidation potential in solution vs. Fc⁺/Fc couple lessthan about 0.6 V.

Non-limiting examples of the HIL and HTL materials that may be used inan OLED in combination with materials disclosed herein are exemplifiedbelow together with references that disclose those materials:CN102702075, DE 102012005215, EP01624500, EP01698613, EP01806334,EP01930964, EP01972613, EP01997799, EP02011790, EP02055700, EP02055701,EP1725079, EP2085382, EP2660300, EP650955, JP07-073529, JP2005112765,JP2007091719, JP2008021687, JP2014-009196, KR20110088898, KR20130077473,TW201139402, U.S. Ser. No. 06/517,957, US20020158242, US20030162053,US20050123751, US20060182993, US20060240279, US20070145888,US20070181874, US20070278938, US20080014464, US20080091025,US20080106190, US20080124572, US20080145707, US20080220265,US20080233434, US20080303417, US2008107919, US20090115320,US20090167161, US2009066235, US2011007385, US20110163302, US2011240968,US2011278551, US2012205642, US2013241401, US20140117329, US2014183517,U.S. Pat. No. 5,061,569, U.S. Pat. No. 5,639,914, WO05075451,WO07125714, WO08023550, WO08023759, WO2009145016, WO2010061824,WO2011075644, WO2012177006, WO2013018530, WO2013039073, WO2013087142,WO2013118812, WO2013120577, WO2013157367, WO2013175747, WO2014002873,WO2014015935, WO2014015937, WO2014030872, WO2014030921, WO2014034791,WO2014104514, WO2014157018.

EBL:

An electron blocking layer (EBL) may be used to reduce the number ofelectrons and/or excitons that leave the emissive layer. The presence ofsuch a blocking layer in a device may result in substantially higherefficiencies, and or longer lifetime, as compared to a similar devicelacking a blocking layer. Also, a blocking layer may be used to confineemission to a desired region of an OLED. In some embodiments, the EBLmaterial has a higher LUMO (closer to the vacuum level) and/or highertriplet energy than the emitter closest to the EBL interface. In someembodiments, the EBL material has a higher LUMO (closer to the vacuumlevel) and or higher triplet energy than one or more of the hostsclosest to the EBL interface. In one aspect, the compound used in EBLcontains the same molecule or the same functional groups used as one ofthe hosts described below.

Additional Hosts:

The light emitting layer of the organic EL device of the presentinvention preferably contains at least a metal complex as light emittingmaterial, and may contain a host material using the metal complex as adopant material. Examples of the host material are not particularlylimited, and any metal complexes or organic compounds may be used aslong as the triplet energy of the host is larger than that of thedopant. Any host material may be used with any dopant so long as thetriplet criteria is satisfied.

Examples of metal complexes used as host are preferred to have thefollowing general formula:

wherein Met is a metal; (Y¹⁰³-Y¹⁰⁴) is a bidentate ligand, Y¹⁰¹ and Y¹⁰⁴are independently selected from C, N, O, P, and S; L¹⁰¹ is an anotherligand; k′ is an integer value from 1 to the maximum number of ligandsthat may be attached to the metal; and k′+k″ is the maximum number ofligands that may be attached to the metal.

In one aspect, the metal complexes are:

wherein (O—N) is a bidentate ligand, having metal coordinated to atoms Oand N.

In another aspect. Met is selected from Ir and Pt. In a further aspect,(Y¹⁰³-Y¹⁰⁴) is a carbene ligand.

Examples of other organic compounds used as additional host are selectedfrom the group consisting of aromatic hydrocarbon cyclic compounds suchas benzene, biphenyl, triphenyl, triphenylene, tetraphenylene,naphthalene, anthracene, phenalene, phenanthrene, fluorene, pyrene,chrysene, perylene, and azulene; the group consisting of aromaticheterocyclic compounds such as dibenzothiophene, dibenzofuran,dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene,benzoselenophene, carbazole, indolocarbazole, pyridylindole,pyrrolodipyridine, pyrazole, imidazole, triazole, oxazole, thiazole,oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine,pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine,indole, benzimidazole, indazole, indoxazine, benzoxazole, benzisoxazole,benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline,quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine,phenazine, phenothiazine, phenoxazine, benzofuropyridine,furodipyridine, benzothienopyridine, thienodipyridine,benzoselenophenopyridine, and selenophenodipyridine; and the groupconsisting of 2 to 10 cyclic structural units which are groups of thesame type or different types selected from the aromatic hydrocarboncyclic group and the aromatic heterocyclic group and are bonded to eachother directly or via at least one of oxygen atom, nitrogen atom, sulfuratom, silicon atom, phosphorus atom, boron atom, chain structural unitand the aliphatic cyclic group. Each option within each may beunsubstituted or may be substituted by a substituent selected from thegroup consisting of deuterium, halide, alkyl, cycloalkyl, heteroalkyl,arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylicacids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl,phosphino, and combinations thereof.

In one aspect, the host compound contains at least one of the followinggroups in the molecule:

wherein each of R¹⁰¹ to R¹⁰⁷ is independently selected from the groupconsisting of hydrogen, deuterium, halide, alkyl, cycloalkyl,heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl,carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl,sulfonyl, phosphino, and combinations thereof, and when it is aryl orheteroaryl, it has the similar definition as Ar's mentioned above. k isan integer from 0 to 20 or 1 to 20. k′″ is an integer from 0 to 20. X¹⁰¹to X¹⁰⁸ is selected from C (including CH) or N. Z¹⁰¹ and Z¹⁰² isselected from NR¹⁰¹, O, or S.

Non-limiting examples of additional host materials that may be used inan OLED in combination with the materials disclosed herein areexemplified below together with references that disclose thosematerials: EP2034538, EP2034538A, EP2757608, JP2007254297,KR20100079458, KR20120088644, KR20120129733, KR20130115564, TW201329200,US20030175553, US20050238919, US20060280965, US20090017330,US20090030202, US20090167162, US20090302743, US20090309488,US20100012931, US20100084966, US20100187984, US2010187984, US2012075273,US2012126221, US2013009543, US2013105787, US2013175519, US2014001446,US20140183503, US20140225088, US2014034914, U.S. Pat. No. 7,154,114,WO2001039234, WO2004093207, WO2005014551, WO2005089025, WO2006072002,WO2006114966, WO2007063754, WO2008056746, WO2009003898, WO2009021126,WO2009063833, WO2009066778, WO2009066779, WO2009086028, WO2010056066,WO2010107244, WO2011081423, WO2011081431, WO2011086863, WO2012128298,WO2012133644, WO2012133649, WO2013024872, WO2013035275, WO2013081315,WO2013191404, WO2014142472.

Emitter:

An emitter dopant is not particularly limited, and any compounds may beused as long as the compounds are typically used as emitter materials.Examples of suitable emitter materials include, but are not limited to,compounds which can produce emissions via phosphorescence, fluorescence,thermally activated delayed fluorescence, i.e., TADF (also referred toas E-type delayed fluorescence), triplet-triplet annihilation, orcombinations of these processes.

Non-limiting examples of the emitter materials that may be used in anOLED in combination with materials disclosed herein are exemplifiedbelow together with references that disclose those materials:CN103694277, CN1696137, EB01238981, EP01239526, EP01961743, EP1239526,EP1244155, EP1642951, EP1647554, EP1841834, EP1841834B, EP2062907,EP2730583, JP2012074444, JP2013110263, JP4478555, KR1020090133652,KR20120032054, KR20130043460, TW201332980, U.S. Ser. No. 06/699,599,U.S. Ser. No. 06/916,554, US20010019782, US20020034656, US20030068526,US20030072964. US20030138657, US20050123788, US20050244673,US2005123791, US2005260449, US20060008670, US20060065890, US20060127696,US20060134459, US20060134462, US20060202194, US20060251923,US20070034863, US20070087321, US20070103060, US20070111026.US20070190359, US20070231600, US2007034863, US2007104979, US2007104980,US2007138437, US2007224450, US2007278936. US20080020237, US20080233410,US20080261076, US20080297033. US200805851, US2008161567. US2008210930,US20090039776, US20090108737, US20090115322, US20090179555,US2009085476, US2009104472, US20100090591, US20100148663, US20100244004,US20100295032, US2010102716, US2010105902, US2010244004, US2010270916,US20110057559, US20110108822, US20110204333, US2011215710, US2011227049,US2011285275, US2012292601, US20130146848, US2013033172, US2013165653,US2013181190, US2013334521, US20140246656, US2014103305, U.S. Pat. No.6,303,238, U.S. Pat. No. 6,413,656, U.S. Pat. No. 6,653,654, U.S. Pat.No. 6,670,645, U.S. Pat. No. 6,687,266, U.S. Pat. No. 6,835,469. U.S.Pat. No. 6,921,915, U.S. Pat. No. 7,279,704, U.S. Pat. No. 7,332,232,U.S. Pat. No. 7,378,162, U.S. Pat. No. 7,534,505, U.S. Pat. No.7,675,228, U.S. Pat. No. 7,728,137, U.S. Pat. No. 7,740,957, U.S. Pat.No. 7,759,489, U.S. Pat. No. 7,951,947, U.S. Pat. No. 8,067,099. U.S.Pat. No. 8,592,586, U.S. Pat. No. 8,871,361, WO06081973. WO06121811,WO07018067, WO07108362, WO07115970. WO07115981, WO08035571,WO2002015645, WO2003040257, WO2005019373 WO2006056418. WO2008054584,WO2008078800, WO2008096609, WO2008101842, WO2009000673, WO2009050281,WO2009100991, WO2010028151, WO2010054731, WO2010086089, WO2010118029,WO2011044988, WO2011051404, WO2011107491, WO2012020327, WO2012163471,WO2013094620, WO2013107487, WO2013174471, WO2014007565, WO2014008982,WO2014023377, WO2014024131, WO2014031977, WO2014038456, WO2014112450.

A hole blocking layer (HBL) may be used to reduce the number of holesand/or excitons that leave the emissive layer. The presence of such ablocking layer in a device may result in substantially higherefficiencies and/or longer lifetime as compared to a similar devicelacking a blocking layer. Also, a blocking layer may be used to confineemission to a desired region of an OLED. In some embodiments, the HBLmaterial has a lower HOMO (further from the vacuum level) and or highertriplet energy than the emitter closest to the HBL interface. In someembodiments, the HBL material has a lower HOMO (further from the vacuumlevel) and or higher triplet energy than one or more of the hostsclosest to the HBL interface.

In one aspect, compound used in HBL contains the same molecule or thesame functional groups used as host described above.

In another aspect, compound used in HBL contains at least one of thefollowing groups in the molecule:

wherein k is an integer from 1 to 20; L¹⁰¹ is an another ligand. k′ isan integer from 1 to 3.

ETL:

Electron transport layer (ETL) may include a material capable oftransporting electrons. Electron transport layer may be intrinsic(undoped), or doped. Doping may be used to enhance conductivity.Examples of the ETL material are not particularly limited, and any metalcomplexes or organic compounds may be used as long as they are typicallyused to transport electrons.

In one aspect, compound used in ETL contains at least one of thefollowing groups in the molecule:

wherein R¹⁰¹ is selected from the group consisting of hydrogen,deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy,aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl,aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile,isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinationsthereof, when it is aryl or heteroaryl, it has the similar definition asAr's mentioned above. Ar¹ to Ar³ has the similar definition as Ar'smentioned above. k is an integer from 1 to 20. X¹⁰¹ to X¹⁰⁸ is selectedfrom C (including CH) or N.

In another aspect, the metal complexes used in ETL contain, but are notlimited to the following general formula:

wherein (O—N) or (N—N) is a bidentate ligand, having metal coordinatedto atoms O, N or N, N; L¹⁰¹ is another ligand; k′ is an integer valuefrom 1 to the maximum number of ligands that may be attached to themetal.

Non-limiting examples of the ETL materials that may be used in an OLEDin combination with materials disclosed herein are exemplified belowtogether with references that disclose those materials: CN103508940,EP01602648. EP01734038, EP01956007, JP2004-022334, JP2005149918,JP2005-268199, KR0117693, KR20130108183, US20040036077, US20070104977,US2007018155, US20090101870. US20090115316, US20090140637,US20090179554, US2009218940, US2010108990, US2011156017, US2011210320,US2012193612, US2012214993, US2014014925, US2014014927, US20140284580,U.S. Pat. No. 6,656,612, U.S. Pat. No. 8,415,031, WO2003060956,WO2007111263, WO2009148269, WO2010067894, WO2010072300, WO2011074770,WO2011105373, WO2013079217, WO2013145667, WO2013180376, WO2014104499,WO2014104535.

Charge Generation Layer (CGL):

In tandem or stacked OLEDs, the CGL plays an essential role in theperformance, which is composed of an n-doped layer and a p-doped layerfor injection of electrons and holes, respectively. Electrons and holesare supplied from the CGL and electrodes. The consumed electrons andholes in the CGL are refilled by the electrons and holes injected fromthe cathode and anode, respectively; then, the bipolar currents reach asteady state gradually. Typical CGL materials include n and pconductivity dopants used in the transport layers.

In any above-mentioned compounds used in each layer of the OLED device,the hydrogen atoms can be partially or fully deuterated. Thus, anyspecifically listed substituent, such as, without limitation, methyl,phenyl, pyridyl, etc. may be undeuterated, partially deuterated, andfully deuterated versions thereof. Similarly, classes of substituentssuch as, without limitation, alkyl, aryl, cycloalkyl, heteroaryl, etc.also may be undeuterated, partially deuterated, and fully deuteratedversions thereof.

Experimental

Materials Synthesis

Chemical abbreviations used throughout this document are as follows:Pd₂(dba)₃ is tri(dibenzylideneacetone) dipalladium(0), and SPhos isdicyclohexyl(2′,6′-dimethoxy-[1,1′-biphenyl]-2-yl)phosphine.

Synthesis of Compound A2

A mixture solution of5-([1,1′-biphenyl]-4-yl)-5,8-dihydroindolo[2,3-c]carbazole (2 g, 4.90mmol), 4-bromo-1,1′:4′,1″-terphenyl (1.817 g, 5.88 mmol), Pd₂(dba)(0.224 g, 0.245 mmol), SPhos (0.201 g, 0.490 mmol) and tert-BuONa (1.18g, 12.24 mmol) in xylene (80 ml) was refluxed under nitrogen for 16 h.The hot reaction mixture was filtered through a short plug of silicagel. Upon evaporation of the solvent, the residue was recrystallizedfrom toluene and triturated with ethyl acetate to yield Compound A2(1.84 g, 59%) as a white solid.

Synthesis of Compound B2

The procedure for the synthesis of Compound A2 was followed tosynthesize Compound B2 from5-([1,1′-biphenyl]-4-yl)-5,8-dihydroindolo[2,3-c]carbazole and3-bromo-1,1′:4′,1″-terphenyl. Compound B2 was synthesized as a whitesolid in a yield of 85%.

Synthesis of Compound D7

The procedure for the synthesis of Compound A2 was followed tosynthesize Compound D7 from5-([1,1′:4′,1″-terphenyl]-3-yl)-5,12-dihydroindolo[3,2-a]carbazole and2-bromo-9,9-dimethyl-9H-fluorene. Compound D7 was synthesized as a whitesolid in a yield of 50%.

Application in OLED.

All devices were fabricated by high vacuum (˜10⁻⁷ Torr) thermalevaporation. The anode electrode was 80 nm of indium tin oxide (ITO).The cathode electrode consisted of 1 nm of LiQ followed by 100 nm of A1.All devices were encapsulated with a glass lid sealed with an epoxyresin in a nitrogen glove box (<1 ppm of H₂O and O₂) immediately afterfabrication, and a moisture getter was incorporated inside the package.

Device Examples

A set of device examples have organic stacks consisting of, sequentiallyfrom the ITO surface, 10 nm of LG101 (from LG Chem) as the holeinjection layer (HIL), 45 nm of PPh-TPD as the hole-transport layer(HTL), 40 nm of emissive layer (EML), 35 nm of compound EH-1 as thehole-blocking layer (HBL), followed by 35 nm of aDBT-ADN with 35 wt %LiQ as the electron-transport layer (ETL). The EML has two components:90 wt % of the EML being the invented compounds (Compound A2 or CompoundD7) or comparative compound (CC-1 or CC-2) as the host and 10 wt % ofthe EML being compound GD as the emitter. The chemical structures of thecompounds used are shown below:

Provided in Table D1 below is a summary of the device data, emissioncolor, power efficiency (PE) and relative lifetime LT97, recorded at1000 nits for device examples. The relative lifetime LT80 (in arbitraryunit. A. U.), defined as the time it takes for a device to decay to 80%of its original luminescence under a constant operation current densitythat provides an initial luminescence of 1000 nits, is calculated fromthe measured value recorded at 40 mA/cm², assuming an accelerationfactor of 1.8, and is normalized to that of Device C-1.

TABLE D1 EML Emission PE LT80 Device ID Host Emitter Color [lm/W] [A.U.]Device 1 Compound A2 GD Green 41.2 177 Device C-1 CC-1 GD Green 40.6 100Device 2 Compound D7 GD Green 17.7 246 Device C-2 CC-2 GD Green 12.0 93

The device data in Table D1 shows that the inventive Compounds A2 and D7produce longer lifetime, while maintaining equivalent or higherefficiency, than their corresponding comparative compounds CC-1 andCC-2, respectively. The enhanced performance of inventive compoundsmight be attributable to the extended conjugation of the terphenylmoiety than the biphenyl moiety, which could improve charge transportproperties of the inventive compounds.

Provided in Table PM below is a summary of the compatibility of selectedh- and e-hosts was evaluated by compositional analysis of filmsfabricated by single-source co-evaporation of the premixture of thesetwo components. A first set of potential premixtures of selected h- ande-hosts are presented in Table PM.

TABLE PM Potential premixtures comprising selected h- and e-hostsPremixtures e-hosts h-hosts PM-1 Compound F5 Compound B2 PM-2 CompoundF5 Compound A3 PM-3 Compound F11 Compound C2 PM-4 Compound F11 CompoundB15 PM-5 Compound F14 Compound A9 PM-6 Compound F14 Compound A38 PM-7Compound F14 Compound B22 PM-8 Compound F17 Compound A3 PM-9 CompoundF17 Compound B2 PM-10 Compound F17 Compound C5 PM-11 Compound H74Compound A35 PM-12 Compound H74 Compound D1 PM-13 Compound H83 CompoundB2 PM-14 Compound H83 Compound A3 PM-15 Compound H248 Compound E14 PM-16Compound M2 Compound C1 PM-17 Compound M5 Compound D6 PM-18 Compound G9Compound B2 PM-19 Compound M101 Compound B5 PM-20 Compound G0 CompoundB2

Premixture PM-1:

Compound F5 and Compound B2 were provided at a weight ratio of 1:1,physically mixed, grinded and loaded into an evaporation source. Thepremixed compositions were thermally co-evaporated at a rate of 2 Å/s ina vacuum chamber under a pressure less than 10⁻⁷ Torr. and depositedonto glass substrates. The substrates were replaced continuously afterdeposition of 500 Å of film without stopping the deposition and coolingthe source. The compositions of films were analyzed by high-performanceliquid chromatography (HPLC) and the results are shown in Table 1.

TABLE 1 HPLC composition (%) of sequentially deposited films form apremixture (PM-1) comprising Compound F5 and Compound B2 with weightratio 1:1. HPLC Conditions: C18 reverse column, 100% acetonitrile asmobile phase, detection wavelength wavelength 254 nm. Due to differentabsorption coefficients, the HPLC composition may or may not agree withthe weight ratio. F5 B2 Plate1 55.7 44.3 Plate2 56.1 43.9 Plate3 52.247.8 Plate4 46.5 53.5

Premixture PM-9:

Premixture PM-9 comprising Compound F17 and Compound B2 were evaluatedin the same way as premixture PM-1, except that a weight ratio of 1:1for Compound F17 and Compound B2 was used, and the results are presentedin Table 2.

TABLE 2 HPLC composition (%) of sequentially deposited films fromPremixture PM-9 comprising Compound E17 and Compound B2 with weightratio 1:1. HPLC Conditions: C18 reverse column, 100% acetonitrile asmobile phase, detection wavelength wavelength 254 nm. Due to differentabsorption coefficients, the HPLC composition may or may not agree withthe weight ratio. F17 B2 Plate1 58.7 41.3 Plate2 60.7 39.3 Plate3 62.137.9 Plate4 63.4 36.6 Plate5 64.8 35.2

Premixture PM-13:

Premixture PM-13 comprising Compound H83 and Compound B2 were evaluatedin the same way as premixture PM-9, and the results are presented inTable 3.

TABLE 3 HPLC composition (%) of sequentially deposited films fromPremixture PM-13 comprising Compound H83 and Compound B2 with weightratio 1:1. HPLC Conditions: C18 reverse column, 100% acetonitrile asmobile phase, detection wavelength wavelength 254 nm. Due to differentabsorption coefficients, the HPLC composition may or may not agree withthe weight ratio. H83 B2 Plate1 53.4 46.6 Plate2 55.0 45.0 Plate3 55.644.4

Premixtures PM-18, PM-19, and PM-20:

Each pair of premixable h-host and e-host at a weight ratio of 1:1 or1:3 was physically mixed, grinded, and loaded into an evaporationsource. The total weight of the mixture was 0.4 g. The premixedcomponents were thermally co-evaporated at a rate of 2 Å/s in a vacuumchamber under a pressure less than 10⁻⁷ Torr until depletion, anddeposited onto glass substrates. The substrates were replacedcontinuously after deposition of 400 Å of film without stopping thedeposition and cooling the source. The compositions of the films wereanalyzed by high-performance liquid chromatography (HPLC) and theresults are shown in Table 4.

TABLE 4 Experimental HPLC data on Premixability for Premixtures PM-18,PM-19, and PM-20 Ratio in H-Host/E-host ratio in deposited films [%]Premixture mixture 1 2 3 4 5 6 7 8 9 PM-18 H-Host B2 1 39.2 38.0 36.835.8 35.5 35.7 35.7 35.9 35.7 E-host G9 1 60.8 62.0 63.2 64.2 64.5 64.364.3 64.1 64.3 PM-19 H-Host B5 1 51.9 50.7 50.1 50.3 50.2 49.9 50.3 50.4E-host M101 1 48.1 49.3 49.9 49.7 49.8 50.1 49.7 49.6 PM-20 H-Host B2 373.9 72.7 70.7 69.2 68.8 69.9 70.9 E-host G10 1 26.1 27.3 29.3 30.8 31.230.1 29.1

The data in Tables 1, 2, 3, and 4 show that the ratio of the twocomponents in premixtures PM-1, PM-9, PM-13, PM-18, PM-19, and PM-20does not change significantly over a continuous single-sourcecoevaporation. The minor fluctuations in the concentrations do notreveal any trend and can be explained by the accuracy of HPLC analysis.Normally, the change of the concentration before and after depositionswithin 5% throughout the process is considered to be good and useful forcommercial OLED application. These experiments conclude that PM-1, PM-9and PM-13 are stable premixtures for coevaporation. The coevaporationstability of these premixtures is believed to tracable to the uniquechemical structures associated with these two classes of materials.

It is understood that the various embodiments described herein are byway of example only, and are not intended to limit the scope of theinvention. For example, many of the materials and structures describedherein may be substituted with other materials and structures withoutdeviating from the spirit of the invention. The present invention asclaimed may therefore include variations from the particular examplesand preferred embodiments described herein, as will be apparent to oneof skill in the art. It is understood that various theories as to whythe invention works are not intended to be limiting.

1. A composition of materials comprising a first compound and a secondcompound, wherein the first compound has a formula selected from thegroup consisting of Formula I and Formula II:

wherein R is selected from the group consisting of:

wherein R⁴ is selected from the group consisting of alkyl, alkoxy,silyl, aryl, heteroaryl, and combinations thereof; wherein R¹, R² and R³each independently represents mono to maximum allowable substitutions,or no substitution; wherein R¹, R² and R³ are each independentlyselected from the group consisting of hydrogen, deuterium, alkyl,alkenyl, alkyne, alkoxy, halogen, silyl, nitrile, nitro, aryl,heteroaryl and combinations thereof; wherein any two adjacentsubstituents are optionally joined or fused into a ring; wherein R⁴, R¹,R², and R³ are each independently, optionally, further substituted withone or more substituents selected from the group consisting of hydrogen,deuterium, alkyl, alkenyl, alkyne, alkoxy, halogen, silyl, nitrile,nitro, aryl, heteroaryl, and combinations thereof; and wherein anyhydrogen in the compound is optionally replaced with deuterium; andwherein the second compound is selected from the group consisting ofFormula III and Formula IV:

wherein G¹ is selected from the group consisting of dibenzofuran,dibenzothiophene, dibenzoselenophene, triphenylene, and fluorene;wherein L¹, L², and L³ are each independently selected from the groupconsisting of a direct bond, phenyl, biphenyl, terphenyl, pyridine,pyrimidine, and combinations thereof; wherein G⁴ is selected from thegroup consisting of phenyl, biphenyl, terphenyl, naphthalene,phenanthrene, triphenylene, pyridine, pyrimidine, pyrazine, quinoline,isoquinoline, phenanthroline, and combinations thereof; wherein G², G³,and G⁵ are each independently selected from the group consisting ofphenyl, biphenyl, terphenyl, fluorene, naphthalene, phenanthrene,pyridine, pyrimidine, pyrazine, quinoline, isoquinoline, phenanthroline,aza-fluorene, carbazole, and combinations thereof; wherein G¹, G², G³,G⁴, and G⁵ are each optionally further substituted with one or moreunfused substituents selected from the group consisting of deuterium,alkyl, alkoxyl, cycloalkyl, cycloalkoxyl, halogen, nitro, nitrile,silyl, phenyl, biphenyl, terphenyl, pyridine, and combinations thereof;wherein m is an integer from 0 to 7, wherein n is an integer from 0 to4; wherein, when m or n is larger than 1, each G⁴ or G⁵ can be the sameor different; wherein when n is 0, then m is equal to or greater than 1,and each G⁴ is selected from the group consisting of phenyl andbiphenyl; wherein when n is equal to or greater than 1, L¹ is not adirect bond; and wherein when m and n are both 0, L¹ is biphenyl; and

wherein L⁴ and L⁵ are each independently selected from the groupconsisting of a direct bond, phenyl, biphenyl, terphenyl, pyridine,pyrimidine, and combinations thereof; wherein R⁵, R⁶, and R⁷ eachrepresent mono to the maximum allowable substitution, or nosubstitution; wherein R⁸ and R⁹ are each independently a substituted orunsubstituted aryl or heteroaryl group; wherein at least one of R⁸ andR⁹ is selected from the group consisting of:

wherein R¹⁰ represents mono to the maximum allowable substitution, or nosubstitution; wherein R⁵, R⁶, R⁷, R¹⁰, and R¹¹ are each independentlyselected from the group consisting of hydrogen, deuterium, halide,alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl,acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, and combinations thereof; and wherein anytwo substituents may be joined or fused together to form a ring. 2.-7.(canceled)
 8. The composition of claim 1, wherein G², G³ and G⁵ areindependently selected from the group consisting of:

wherein R^(B1) and R^(B2) are independently selected from a groupconsisting of hydrogen, deuterium, alkyl, alkenyl, cycloalkyl, alkoxyl,aryl, heteraryl, halogen, and combinations thereof; and wherein R^(B1)and R^(B2) are optionally joined to form a ring.
 9. The composition ofclaim 1, wherein R⁸ and R⁹ are independently selected from the groupconsisting of:


10. The composition of claim 1, wherein L⁴ is a direct bond, and L⁵ is aphenyl ring.
 11. The composition of claim 1, wherein the second compoundhas the formula:

wherein X is selected from the group consisting of O, S and Se; whereinA¹ represents mono to the maximum allowable substitution, or nosubstitution; and wherein each A¹, A², and A³ is independently selectedfrom the group consisting of hydrogen, phenyl, biphenyl, terphenyl,naphthalene, and combinations thereof.
 12. The composition of claim 1,wherein the second compound is selected from the group consisting of:Compound Fl through F3, each represented by the formula

wherein in Compound F1: X = O, in Compound F2: X = S, in Compound F3: X= Se Compound F4 through F6, each represented by the formula

wherein in Compound F4: X = O, in Compound F5: X = S, in Compound F6: X= Se Compound F7 through F9, each represented by the formula

wherein in Compound F7: X = O, in Compound F8: X = S, in Compound F9: X= Se Compound F10 through F12, each represented by the formula

wherein in Compound F10: X = O, in Compound F11: X = S, in Compound F12:X = Se Compound F13 through F15, each represented by the formula

wherein in Compound F13: X = O, in Compound F14: X = S, in Compound F15:X = Se Compound F16 through F18, each represented by the formula

wherein in Compound F16: X = O, in Compound F17: X = S, in Compound F18:X = Se Compound F19 through F21, each represented by the formula

wherein in Compound F19: X = O, in Compound F20: X = S, in Compound F21:X = Se Compound F22 through F24, each represented by the formula

wherein in Compound F22: X = O, in Compound F23: X = S, in Compound F24:X = Se Compound F25 through F27, each represented by the formula

wherein in Compound F25: X = O, in Compound F26: X = S, in Compound F27:X = Se Compound F28 through F30, each represented by the formula

wherein in Compound F28: X = O, in Compound F29: X = S, in Compound F30:X = Se Compound F31 through F33, each represented by the formula

wherein in Compound F31: X = O, in Compound F32: X = S, in Compound F33:X = Se Compound F34 through F36, each represented by the formula

wherein in Compound F34: X = O, in Compound F35: X = S, in Compound F36:X = Se Compound F37 through F39, each represented by the formula

wherein in Compound F37: X = O, in Compound F38: X = S, in Compound F39:X = Se Compound F40 through F42, each represented by the formula

wherein in Compound F40: X = O, in Compound F41: X = S, in Compound F42:X = Se Compound F43 through F45, each represented by the formula

wherein in Compound F43: X = O, in Compound F44: X = S, in Compound F45:X = Se Compound F46 through F48, each represented by the formula

wherein in Compound F46: X = O, in Compound F47: X = S, in Compound F48:X = Se Compound F49 through F51, each represented by the formula

wherein in Compound F49: X = O, in Compound F50: X = S, in Compound F51:X = Se Compound F52 through F54, each represented by the formula

wherein in Compound F52: X = O, in Compound F53: X = S, in Compound F54:X = Se Compound F55 through F57, each represented by the formula

wherein in Compound F55: X = O, in Compound F56: X = S, in Compound F57:X = Se Compound F58 through F60, each represented by the formula

wherein in Compound F58: X = O, in Compound F59: X = S, in Compound F60:X = Se Compound F61 through F63, each represented by the formula

wherein in Compound F61: X = O, in Compound F62: X = S, in Compound F63:X = Se Compound F64 through F66, each represented by the formula

wherein in Compound F64: X = O, in Compound F65: X = S, in Compound F66:X = Se Compound F67 through F69, each represented by the formula

wherein in Compound F67: X = O, in Compound F68: X = S, in Compound F69:X = Se Compound F70 through F72, each represented by the formula

wherein in Compound F70: X = O, in Compound F71: X = S, in Compound F72:X = Se Compound F73 through F75, each represented by the formula

wherein in Compound F73: X = O, in Compound F74: X = S, in Compound F75:X = Se Compound F76 through F78, each represented by the formula

wherein in Compound F76: X = O, in Compound F77: X = S, in Compound F78:X = Se Compound F79 through F81, each represented by the formula

wherein in Compound F79: X = O, in Compound F80: X = S, in Compound F81:X = Se Compound F82 through F84, each represented by the formula

wherein in Compound F82: X = O, in Compound F83: X = S, in Compound F84:X = Se Compound F85 through F87, each represented by the formula

wherein in Compound F85: X = O, in Compound F86: X = S, in Compound F87:X = Se Compound F88 through F90, each represented by the formula

wherein in Compound F88: X = O, in Compound F89: X = S, in Compound F90:X = Se Compound F91 through F93, each represented by the formula

wherein in Compound F91: X = O, in Compound F92: X = S, in Compound F93:X = Se Compound F94 through F96, each represented by the formula

wherein in Compound F94: X = O, in Compound F95: X = S, in Compound F96:X = Se Compound F97 through F99, each represented by the formula

wherein in Compound F97: X = O, in Compound F98: X = S, in Compound F99:X = Se Compound F100 through F102, each represented by the formula

wherein in Compound F100: X = O, in Compound F101: X = S, in CompoundF102: X = Se Compound F103 through F105, each represented by the formula

wherein in Compound F103: X = O, in Compound F104: X = S, in CompoundF105: X = Se Compound F106 through F108, each represented by the formula

wherein in Compound F106: X = O, in Compound F107: X = S, in CompoundF108: X = Se Compound F109 through F111, each represented by the formula

wherein in Compound F109: X = O, in Compound F110: X = S, in CompoundF111: X = Se Compound F112 through F114, each represented by the formula

wherein in Compound F112: X = O, in Compound F113: X = S, in CompoundF114: X = Se Compound F115 through F117, each represented by the formula

wherein in Compound F115: X = O, in Compound F116: X = S, in CompoundF117: X = Se

Compound G1

Compound G2

Compound G3

Compound G4

Compound G5

Compound G6

Compound G7

Compound G8

Compound G9

Compound G10

Compound G11

Compound G12

Compound G13

Compound G14

Compound G15

Compound G16

Compound G17

Compound G18

Compound G19

Compound G20

Compound G21

Compound G22

Compound G23

Compound G24

Compound G25

Compound G26

Compound G27

Compound G28

Compound G29

Compound G30

Compound G31

Compound G32

Compound G33

Compound G34

Compound G35

Compound G36 Compound H1 through H3, each represented by the formula

wherein in Compound H1: X = O, in Compound H2: X = S, in Compound H3: X= Se Compound H4 through H6, each represented by the formula

wherein in Compound H4: X = O, in Compound H5: X = S, in Compound H6: X= Se Compound H7 through H9, each represented by the formula

wherein in Compound H7: X = O, in Compound H8: X = S, in Compound H9: X= Se Compound H10 through H12, each represented by the formula

wherein in Compound H10: X = O, in Compound H11: X = S, in Compound H12:X = Se Compound H13 through H15, each represented by the formula

wherein in Compound H13: X = O, in Compound H14: X = S, in Compound H15:X = Se Compound H16 through H18, each represented by the formula

wherein in Compound H16: X = O, in Compound H17: X = S, in Compound H18:X = Se Compound H19 through H21, each represented by the formula

wherein in Compound H19: X = O, in Compound H20: X = S, in Compound H21:X = Se Compound H22 through H24, each represented by the formula

wherein in Compound H22: X = O, in Compound H23: X = S, in Compound H24:X = Se Compound H25 through H27, each represented by the formula

wherein in Compound H25: X = O, in Compound H26: X = S, in Compound H27:X = Se Compound H28 through H30, each represented by the formula

wherein in Compound H28: X = O, in Compound H29: X = S, in Compound H30:X = Se Compound H31 through H32, each represented by the formula

wherein in Compound H31: X = O, in Compound H32: X = S, in Compound H30:X = Se Compound H34 through H36, each represented by the formula

wherein in Compound H34: X = O, in Compound H35: X = S, in Compound H36:X = Se Compound H37 through H39, each represented by the formula

wherein in Compound H37: X = O, in Compound H38: X = S, in Compound H39:X = Se Compound H40 through H42, each represented by the formula

wherein in Compound H40: X = O, in Compound H41: X = S, in Compound H42:X = Se Compound H43 through H45, each represented by the formula

wherein in Compound H43: X = O, in Compound H44: X = S, in Compound H45:X = Se Compound H46 through H48, each represented by the formula

wherein in Compound H46: X = O, in Compound H47: X = S, in Compound H48:X = Se Compound H49 through H51, each represented by the formula

wherein in Compound H49: X = O, in Compound H50: X = S, in Compound H51:X = Se Compound H52 through H54, each represented by the formula

wherein in Compound H52: X = O, in Compound H53: X = S, in Compound H54:X = Se Compound H55 through H57, each represented by the formula

wherein in Compound H55: X = O, in Compound H56: X = S, in Compound H57:X = Se Compound H58 through H60, each represented by the formula

wherein in Compound H58: X = O, in Compound H59: X = S, in Compound H60:X = Se Compound H61 through H63, each represented by the formula

wherein in Compound H61: X = O, in Compound H62: X = S, in Compound H63:X = Se Compound H64 through H66, each represented by the formula

wherein in Compound H64: X = O, in Compound H65: X = S, in Compound H66:X = Se Compound H67 through H69, each represented by the formula

wherein in Compound H67: X = O, in Compound H68: X = S, in Compound H69:X = Se Compound H70 through H72, each represented by the formula

wherein in Compound H70: X = O, in Compound H71: X = S, in Compound H72:X = Se Compound H73 through H75, each represented by the formula

wherein in Compound H73: X = O, in Compound H74: X = S, in Compound H75:X = Se Compound H76 through H78, each represented by the formula

wherein in Compound H76: X = O, in Compound H77: X = S, in Compound H78:X = Se Compound H79 through H81, each represented by the formula

wherein in Compound H79: X = O, in Compound H80: X = S, in Compound H81:X = Se Compound H82 through H84, each represented by the formula

wherein in Compound H82: X = O, in Compound H83: X = S, in Compound H84:X = Se Compound H85 through H87, each represented by the formula

wherein in Compound H85: X = O, in Compound H86: X = S, in Compound H87:X = Se Compound H88 through H90, each represented by the formula

wherein in Compound H88: X = O, in Compound H89: X = S, in Compound H90:X = Se Compound H91 through H93, each represented by the formula

wherein in Compound H91: X = O, in Compound H92: X = S, in Compound H93:X = Se Compound H94 through H96, each represented by the formula

wherein in Compound H94: X = O, in Compound H95: X = S, in Compound H96:X = Se Compound H97 through H99, each represented by the formula

wherein in Compound H97: X = O, in Compound H98: X = S, in Compound H99:X = Se Compound H100 through H102, each represented by the formula

wherein in Compound H100: X = O, in Compound H101: X = S, in CompoundH102: X = Se Compound H103 through H105, each represented by the formula

wherein in Compound H103: X = O, in Compound H104: X = S, in CompoundH105: X = Se Compound H106 through H108, each represented by the formula

wherein in Compound H106: X = O, in Compound H107: X = S, in CompoundH108: X = Se Compound H109 through H111, each represented by the formula

wherein in Compound H109: X = O, in Compound H110: X = S, in CompoundH111: X = Se Compound H112 through H114, each represented by the formula

wherein in Compound H112: X = O, in Compound H113: X = S, in CompoundH114: X = Se Compound H115 through H117, each represented by the formula

wherein in Compound H115: X = O, in Compound H116: X = S, in CompoundH117: X = Se Compound H118 through H120, each represented by the formula

wherein in Compound H118: X = O, in Compound H119: X = S, in CompoundH120: X = Se Compound H121 through H123, each represented by the formula

wherein in Compound H121: X = O, in Compound H122: X = S, in CompoundH123: X = Se Compound H124 through H126, each represented by the formula

wherein in Compound H124: X = O, in Compound H125: X = S, in CompoundH126: X = Se Compound H127 through H129, each represented by the formula

wherein in Compound H127: X = O, in Compound H128: X = S, in CompoundH129: X = Se Compound H130 through H132, each represented by the formula

wherein in Compound H130: X = O, in Compound H131: X = S, in CompoundH132: X = Se Compound H133 through H135, each represented by the formula

wherein in Compound H133: X = O, in Compound H134: X = S, in CompoundH135: X = Se Compound H136 through H138, each represented by the formula

wherein in Compound H136: X = O, in Compound H137: X = S, in CompoundH138: X = Se Compound H139 through H141, each represented by the formula

wherein in Compound H139: X = O, in Compound H140: X = S, in CompoundH141: X = Se Compound H142 through H144, each represented by the formula

wherein in Compound H142: X = O, in Compound H143: X = S, in CompoundH144: X = Se Compound H145 through H147, each represented by the formula

wherein in Compound H145: X = O, in Compound H146: X = S, in CompoundH147: X = Se Compound H148 through H150, each represented by the formula

wherein in Compound H148: X = O, in Compound H149: X = S, in CompoundH150: X = Se Compound H151 through H153, each represented by the formula

wherein in Compound H151: X = O, in Compound H152: X = S, in CompoundH152: X = Se Compound H154 through H156, each represented by the formula

wherein in Compound H154: X = O, in Compound H155: X = S, in CompoundH156: X = Se Compound H157 through H159, each represented by the formula

wherein in Compound H157: X = O, in Compound H158: X = S, in CompoundH159: X = Se Compound H160 through H162, each represented by the formula

wherein in Compound H160: X = O, in Compound H161: X = S, in CompoundH162: X = Se Compound H163 through H165, each represented by the formula

wherein in Compound H163: X = O, in Compound H164: X = S, in CompoundH165: X = Se Compound H166 through H168, each represented by the formula

wherein in Compound H166: X = O, in Compound H167: X = S, in CompoundH168: X = Se Compound H169 through H171, each represented by the formula

wherein in Compound H169: X = O, in Compound H170: X = S, in CompoundH171: X = Se Compound H172 through H174, each represented by the formula

wherein in Compound H172: X = O, in Compound H173: X = S, in CompoundH174: X = Se Compound H175 through H177, each represented by the formula

wherein in Compound H175: X = O, in Compound H176: X = S, in CompoundH177: X = Se Compound H178 through H180, each represented by the formula

wherein in Compound H178: X = O, in Compound H179: X = S, in CompoundH180: X = Se Compound H181 through H183, each represented by the formula

wherein in Compound H181: X = O, in Compound H182: X = S, in CompoundH183: X = Se Compound H184 through H186, each represented by the formula

wherein in Compound H184: X = O, in Compound H185: X = S, in CompoundH186: X = Se Compound H187 through H189, each represented by the formula

wherein in Compound H187: X = O, in Compound H188: X = S, in CompoundH189: X = Se Compound H190 through H192, each represented by the formula

wherein in Compound H190: X = O, in Compound H191: X = S, in CompoundH192: X = Se Compound H193 through H195, each represented by the formula

wherein in Compound H193: X = O, in Compound H194: X = S, in CompoundH195: X = Se Compound H196 through H198, each represented by the formula

wherein in Compound H196: X = O, in Compound H197: X = S, in CompoundH198: X = Se Compound H199 through H201, each represented by the formula

wherein in Compound H199: X = O, in Compound H200: X = S, in CompoundH201: X = Se Compound H202 through H204, each represented by the formula

wherein in Compound H202: X = O, in Compound H203: X = S, in CompoundH204: X = Se Compound H205 through H207, each represented by the formula

wherein in Compound H205: X = O, in Compound H206: X = S, in CompoundH207: X = Se Compound H208 through H210, each represented by the formula

wherein in Compound H208: X = O, in Compound H209: X = S, in CompoundH210: X = Se Compound H211 through H213, each represented by the formula

wherein in Compound H211: X = O, in Compound H212: X = S, in CompoundH213: X = Se Compound H214 through H216, each represented by the formula

wherein in Compound H214: X = O, in Compound H215: X = S, in CompoundH216: X = Se Compound H217 through H219, each represented by the formula

wherein in Compound H217: X = O, in Compound H218: X = S, in CompoundH219: X = Se Compound H220 through H222, each represented by the formula

wherein in Compound H220: X = O, in Compound H221: X = S, in CompoundH222: X = Se Compound H223 through H225, each represented by the formula

wherein in Compound H223: X = O, in Compound H224: X = S, in CompoundH225: X = Se Compound H226 through H228, each represented by the formula

wherein in Compound H226: X = O, in Compound H227: X = S, in CompoundH228: X = Se Compound H229 through H231, each represented by the formula

wherein in Compound H229: X = O, in Compound H230: X = S, in CompoundH231: X = Se Compound H232 through H234, each represented by the formula

wherein in Compound H232: X = O, in Compound H233: X = S, in CompoundH234: X = Se Compound H235 through H237, each represented by the formula

wherein in Compound H235: X = O, in Compound H236: X = S, in CompoundH237: X = Se Compound H238 through H240, each represented by the formula

wherein in Compound H238: X = O, in Compound H239: X = S, in CompoundH240: X = Se Compound H241 through H243, each represented by the formula

wherein in Compound H241: X = O, in Compound H242: X = S, in CompoundH243: X = Se Compound H244 through H246, each represented by the formula

wherein in Compound H244: X = O, in Compound H245: X = S, in CompoundH246: X = Se Compound H247 through H249, each represented by the formula

wherein in Compound H247: X = O, in Compound H248: X = S, in CompoundH249: X = Se Compound H250 through H252, each represented by the formula

wherein in Compound H250: X = O, in Compound H251: X = S, in CompoundH252: X = Se Compound H253 through H255, each represented by theformula:

wherein in Compound H253: X = O, in Compound H254: X = S, in CompoundH255: X = Se Compounds M1 through M3, each represented by the formula:

wherein in Compound M1: X = O, in Compound M2: X = S, and in CompoundM3: X = Se Compounds M4 through M6, each represented by the formula:

wherein in Compound M4: X = O, in Compound M5: X = S, and in CompoundM6: X = Se Compounds M7 through M9, each represented by the formula:

wherein in Compound M7: X = O, in Compound M8: X = S, and in CompoundM9: X = Se Compounds M10 through M12, each represented by the formula:

wherein in Compound M10: X = O, in Compound M11: X = S, and in CompoundM12: X = Se Compounds M13 through M15, each represented by the formula:

wherein in Compound M13: X = O, in Compound M14: X = S, and in CompoundM15: X = Se Compounds M16 through M18, each represented by the formula:

wherein in Compound M16: X = O, in Compound M17: X = S, and in CompoundM18: X = Se Compounds M19 through M21, each represented by the formula:

wherein in Compound M19: X = O, in Compound M20: X = S, and in CompoundM21: X = Se Compounds M22 through M24, each represented by the formula:

wherein in Compound M22: X = O, in Compound M23: X = S, and in CompoundM24: X = Se Compounds M25 through M27, each represented by the formula:

wherein in Compound M25: X = O, in Compound M26: X = S, and in CompoundM27: X = Se Compounds M28 through M30, each represented by the formula:

wherein in Compound M28: X = O, in Compound M29: X = S, and in CompoundM30: X = Se Compounds M31 through M33, each represented by the formula:

wherein in Compound M31: X = O, in Compound M32: X = S, and in CompoundM33: X = Se Compounds M34 through M36, each represented by the formula:

wherein in Compound M34: X = O, in Compound M35: X = S, and in CompoundM36: X = Se Compounds M37 through M39, each represented by the formula:

wherein in Compound M37: X = O, in Compound M38: X = S, and in CompoundM39: X = Se Compounds M40 through M42, each represented by the formula:

wherein in Compound M40: X = O, in Compound M41: X = S, and in CompoundM42: X = Se Compounds M43 through M45, each represented by the formula:

wherein in Compound M43: X = O, in Compound M44: X = S, and in CompoundM45: X = Se Compounds M46 through M48, each represented by the formula:

wherein in Compound M46: X = O, in Compound M47: X = S, and in CompoundM48: X = Se Compounds M49 through M51, each represented by the formula:

wherein in Compound M49: X = O, in Compound M50: X = S, and in CompoundM51: X = Se Compounds M49 through M51, each represented by the formula:

wherein in Compound M52: X = O, in Compound M53: X = S, and in CompoundM54: X = Se Compounds M55 through M57, each represented by the formula:

wherein in Compound M55: X = O, in Compound M56: X = S, and in CompoundM57: X = Se Compounds M58 through M60, each represented by the formula:

wherein in Compound M58: X = O, in Compound M59: X = S, and in CompoundM60: X = Se Compounds M61 through M63, each represented by the formula:

wherein in Compound M61: X = O, in Compound M62: X = S, and in CompoundM63: X = Se Compounds M64 through M66, each represented by the formula:

wherein in Compound M64: X = O, in Compound M65: X = S, and in CompoundM66: X = Se Compounds M67 through M69, each represented by the formula:

wherein in Compound M67: X = O, in Compound M68: X = S, and in CompoundM69: X = Se Compounds M70 through M72, each represented by the formula:

wherein in Compound M70: X = O, in Compound M71: X = S, and in CompoundM72: X = Se Compounds M73 through M75, each represented by the formula:

wherein in Compound M73: X = O, in Compound M74: X = S, and in CompoundM75: X = Se Compounds M76 through M78, each represented by the formula:

wherein in Compound M76: X = O, in Compound M77: X = S, and in CompoundM78: X = Se Compounds M79 through M81, each represented by the formula:

wherein in Compound M79: X = O, in Compound M80: X = S, and in CompoundM81: X = Se Compounds M82 through M84, each represented by the formula:

wherein in Compound M82: X = O, in Compound M83: X = S, and in CompoundM84: X = Se Compounds M85 through M87, each represented by the formula:

wherein in Compound M85: X = O, in Compound M86: X = S, and in CompoundM87: X = Se Compounds M88 through M90, each represented by the formula:

wherein in Compound M88: X = O, in Compound M89: X = S, and in CompoundM90: X = Se Compounds M91 through M93, each represented by the formula:

wherein in Compound M91: X = O, in Compound M92: X = S, and in CompoundM93: X = Se Compounds M94 through M96, each represented by the formula:

wherein in Compound M94: X = O, in Compound M95: X = S, and in CompoundM96: X = Se Compounds M97 through M99, each represented by the formula:

wherein in Compound M97: X = O, in Compound M98: X = S, and in CompoundM99: X = Se Compounds M100 through M102, each represented by theformula:

wherein in Compound M100: X = O, in Compound M101: X = S, and inCompound M102: X = Se Compounds M103 through M105, each represented bythe formula:

wherein in Compound M103: X = O, in Compound M104: X = S, and inCompound M105: X = Se Compounds M106 through M108, each represented bythe formula:

wherein in Compound M106: X = O, in Compound M107: X = S, and inCompound M108: X = Se Compounds M109 through M111, each represented bythe formula:

wherein in Compound M109: X = O, in Compound M110: X = S, and inCompound M111: X = Se Compounds M112 through M114, each represented bythe formula:

wherein in Compound M112: X = O, in Compound M113: X = S, and inCompound M114: X = Se Compounds M115 through M117, each represented bythe formula:

wherein in Compound M115: X = O, in Compound M116: X = S, and inCompound M117: X = Se Compounds M118 through M120, each represented bythe formula:

wherein in Compound M118: X = O, in Compound M119: X = S, and inCompound M120: X = Se Compounds M121 through M123, each represented bythe formula:

wherein in Compound M121: X = O, in Compound M122: X = S, and inCompound M123: X = Se Compounds M124 through M126, each represented bythe formula:

wherein in Compound M124: X = O, in Compound M125: X = S, and inCompound M126: X = Se Compounds M127 through M129, each represented bythe formula:

wherein in Compound M127: X = O, in Compound M128: X = S, and inCompound M129: X = Se Compounds M130 through M132, each represented bythe formula:

wherein in Compound M130: X = O, in Compound M131: X = S, and inCompound M132: X = Se Compounds M133 through M135, each represented bythe formula:

wherein in Compound M133: X = O, in Compound M134: X = S, and inCompound M135: X = Se Compounds M136 through M138, each represented bythe formula:

wherein in Compound M136: X = O, in Compound M137: X = S, and inCompound M138: X = Se Compounds M139 through M141, each represented bythe formula:

wherein in Compound M139: X = O, in Compound M140: X = S, and inCompound M141: X = Se Compounds M142 through M144, each represented bythe formula:

wherein in Compound M142: X = O, in Compound M143: X = S, and inCompound M144: X = Se Compounds M145 through M147, each represented bythe formula:

wherein in Compound M145: X = O, in Compound M146: X = S, and inCompound M147: X = Se Compounds M148 through M150, each represented bythe formula:

wherein in Compound M148: X = O, in Compound M149: X = S, and inCompound M150: X = Se Compounds M151 through M153, each represented bythe formula:

wherein in Compound M151: X = O, in Compound M152: X = S, and inCompound M153: X = Se


13. The composition of claim 1, wherein the first compound is Formula I.14. The composition of claim 1, wherein the first compound has anevaporation temperature T1 of 150 to 350° C.; wherein the secondcompound has an evaporation temperature T2 of 150 to 350° C.; whereinthe absolute value of T1−T2 is less than 20° C.; wherein the firstcompound has a concentration C1 in said mixture and a concentration C2in a film formed by evaporating the mixture in a vacuum deposition toolat a constant pressure between 1×10⁻⁶ Torr to 1×10⁻⁹ Torr, at a 2 Å/secdeposition rate on a surface position at a predefined distance away fromthe mixture being evaporated; and wherein the absolute value of(C1−C2)/C1 is less than 5%. 15.-16. (canceled)
 17. The composition ofclaim 1, wherein the first compound has a vapor pressure of P1 at T1 at1 atm, the second compound has a vapor pressure of P2 at T2 at 1 atm;and wherein the ratio of P1/P2 is within the range of 0.90 to 1.10.18.-20. (canceled)
 21. The composition of claim 1, wherein the firstcompound and the second compound each has a purity in excess of 99% asdetermined by high pressure liquid chromatography.
 22. The compositionof claim 1, wherein the composition further comprises a third compound,wherein the third compound has a different chemical structure than thefirst and second compounds, wherein the third compound has anevaporation temperature T3 of 150 to 350° C., and wherein absolute valueof T1-T3 is less than 20° C.
 23. The composition of claim 1, wherein thecomposition further comprises a third compound, wherein the thirdcompound has a different chemical structure than the first and secondcompounds, wherein the third compound has a third mass loss rate and theratio between the first mass loss rate and third mass loss rate iswithin the range of 0.90 to 1.10
 24. The composition of claim 1, whereinthe composition is in liquid form at a temperature less than T1 and T2.25. An organic light emitting device (OLED) comprising: an anode; acathode; and an organic layer, disposed between the anode and thecathode, comprising a composition of materials comprising a firstcompound and a second compound, wherein the first compound has a formulaselected from the group consisting of Formula I and Formula II:

wherein R is selected from the group consisting of:

wherein R⁴ is selected from the group consisting of alkyl, alkoxy,silyl, aryl, heteroaryl, and combinations thereof; wherein R¹, R² and R³each independently represents mono to maximum allowable substitutions,or no substitution; wherein R¹, R² and R³ are each independentlyselected from the group consisting of hydrogen, deuterium, alkyl,alkenyl, alkyne, alkoxy, halogen, silyl, nitrile, nitro, aryl,heteroaryl and combinations thereof; wherein any two adjacentsubstituents are optionally joined or fused into a ring; wherein R⁴, R¹,R², and R³ are each independently, optionally, further substituted withone or more substituents selected from the group consisting of hydrogen,deuterium, alkyl, alkenyl, alkyne, alkoxy, halogen, silyl, nitrile,nitro, aryl, heteroaryl, and combinations thereof; and wherein anyhydrogen in the compound is optionally replaced with deuterium; andwherein the second compound is selected from the group consisting ofFormula III and Formula IV:

wherein G¹ is selected from the group consisting of dibenzofuran,dibenzothiophene, dibenzoselenophene, triphenylene, and fluorene;wherein L¹, L², and L³ are each independently selected from the groupconsisting of a direct bond, phenyl, biphenyl, terphenyl, pyridine,pyrimidine, and combinations thereof; wherein G⁴ is selected from thegroup consisting of phenyl, biphenyl, terphenyl, naphthalene,phenanthrene, triphenylene, pyridine, pyrimidine, pyrazine, quinoline,isoquinoline, phenanthroline, and combinations thereof; wherein G², G³,and G⁵ are each independently selected from the group consisting ofphenyl, biphenyl, terphenyl, fluorene, naphthalene, phenanthrene,pyridine, pyrimidine, pyrazine, quinoline, isoquinoline, phenanthroline,aza-fluorene, carbazole, and combinations thereof; wherein G¹, G², G³,G⁴, and G⁵ are each optionally further substituted with one or moreunfused substituents selected from the group consisting of deuterium,alkyl, alkoxyl, cycloalkyl, cycloalkoxyl, halogen, nitro, nitrile,silyl, phenyl, biphenyl, terphenyl, pyridine, and combinations thereof;wherein m is an integer from 0 to 7, wherein n is an integer from 0 to4; wherein, when m or n is larger than 1, each G⁴ or G⁵ can be the sameor different; wherein when n is 0, then m is equal to or greater than 1,and each G⁴ is selected from the group consisting of phenyl andbiphenyl; wherein when n is equal to or greater than 1, L¹ is not adirect bond; and wherein when m and n are both 0, L¹ is biphenyl; and

wherein L⁴ and L⁵ are each independently selected from the groupconsisting of a direct bond, phenyl, biphenyl, terphenyl, pyridine,pyrimidine, and combinations thereof; wherein R⁵, R⁶, and R⁷ eachrepresent mono to the maximum allowable substitution, or nosubstitution; wherein R⁸ and R⁹ are each independently a 5-membered or6-membered aromatic ring; wherein at least one of R⁸ and R⁹ is selectedfrom the group consisting of:

wherein R¹⁰ represents mono to the maximum allowable substitution, or nosubstitution; wherein R⁵, R⁶, R⁷, R¹⁰, and R¹¹ are each independentlyselected from the group consisting of hydrogen, deuterium, halide,alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl,acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, and combinations thereof; and wherein anytwo substituents may be joined or fused together to form a ring.
 26. TheOLED of claim 25, wherein the organic layer is an emissive layer and thecompound of Formula I, or II is a host.
 27. The OLED of claim 25,wherein the organic layer further comprises a phosphorescent emissivedopant; wherein the emissive dopant is a transition metal complex havingat least one ligand or part of the ligand if the ligand is more thanbidentate selected from the group consisting of:

wherein each Y¹ to Y¹³ are independently selected from the groupconsisting of carbon and nitrogen; wherein Y′ is selected from the groupconsisting of BR_(e), NR_(e), PR_(e), O, S, Se, C═O, S═O, SO₂,CR_(e)R_(f)RR, SiR_(e)R_(f), and GeR_(e)R_(f); wherein R_(e) and R_(f)are optionally fused or joined to form a ring; wherein each R_(a),R_(b), R_(c), and R_(d) may independently represent from monosubstitution to the maximum possible number of substitution, or nosubstitution; wherein each R_(a), R_(b), R_(c), R_(d), R_(e), and R_(f)is independently selected from the group consisting of hydrogen,deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy,amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl,nitrile, isonitrile, and combinations thereof; and wherein any twoadjacent substituents of R_(a), R_(b), R_(c), and R_(d) are optionallyfused or joined to form a ring or form a multidentate ligand.
 28. TheOLED of claim 25, wherein the organic layer is a blocking layer and thecompound of Formula I, or II is a blocking material in the organiclayer.
 29. The OLED of claim 25, wherein the organic layer is atransporting layer and the compound of Formula I, or II is atransporting material in the organic layer. 30.-31. (canceled)
 32. Aconsumer product comprising an organic light-emitting device (OLED)comprising: an anode; a cathode; and an organic layer, disposed betweenthe anode and the cathode, comprising a composition of materialscomprising a first compound and a second compound, wherein the firstcompound has a formula selected from the group consisting of:

wherein R is selected from the group consisting of:

wherein R⁴ is selected from the group consisting of alkyl, alkoxy,silyl, aryl, heteroaryl, and combinations thereof; wherein R¹, R² and R³each independently represents mono to maximum allowable substitutions,or no substitution; wherein R¹, R² and R³ are each independentlyselected from the group consisting of hydrogen, deuterium, alkyl,alkenyl, alkyne, alkoxy, halogen, silyl, nitrile, nitro, aryl,heteroaryl and combinations thereof; wherein any two adjacentsubstituents are optionally joined or fused into a ring; wherein R⁴, R¹,R², and R³ are each independently, optionally, further substituted withone or more substituents selected from the group consisting of hydrogen,deuterium, alkyl, alkenyl, alkyne, alkoxy, halogen, silyl, nitrile,nitro, aryl, heteroaryl, and combinations thereof; and wherein anyhydrogen in the compound is optionally replaced with deuterium; andwherein the second compound is selected from the group consisting ofFormula III and Formula IV:

wherein G¹ is selected from the group consisting of dibenzofuran,dibenzothiophene, dibenzoselenophene, triphenylene, and fluorene;wherein L¹, L², and L³ are each independently selected from the groupconsisting of a direct bond, phenyl, biphenyl, terphenyl, pyridine,pyrimidine, and combinations thereof; wherein G⁴ is selected from thegroup consisting of phenyl, biphenyl, terphenyl, naphthalene,phenanthrene, triphenylene, pyridine, pyrimidine, pyrazine, quinoline,isoquinoline, phenanthroline, and combinations thereof; wherein G², G³,and G⁵ are each independently selected from the group consisting ofphenyl, biphenyl, terphenyl, fluorene, naphthalene, phenanthrene,pyridine, pyrimidine, pyrazine, quinoline, isoquinoline, phenanthroline,aza-fluorene, carbazole, and combinations thereof; wherein G¹, G², G³,G⁴, and G⁵ are each optionally further substituted with one or moreunfused substituents selected from the group consisting of deuterium,alkyl, alkoxyl, cycloalkyl, cycloalkoxyl, halogen, nitro, nitrile,silyl, phenyl, biphenyl, terphenyl, pyridine, and combinations thereof;wherein m is an integer from 0 to 7, wherein n is an integer from 0 to4; wherein, when m or n is larger than 1, each G⁴ or G⁵ can be the sameor different; wherein when n is 0, then m is equal to or greater than 1,and each G⁴ is selected from the group consisting of phenyl andbiphenyl; wherein when n is equal to or greater than 1, L¹ is not adirect bond; and wherein when m and n are both 0, L¹ is biphenyl; and

wherein L⁴ and L⁵ are each independently selected from the groupconsisting of a direct bond, phenyl, biphenyl, terphenyl, pyridine,pyrimidine, and combinations thereof; wherein R⁵, R⁶, and R⁷ eachrepresent mono to the maximum allowable substitution, or nosubstitution; wherein R⁸ and R⁹ are each independently a 5-membered or6-membered aromatic ring; wherein at least one of R⁸ and R⁹ is selectedfrom the group consisting of:

wherein R¹⁰ represents mono to the maximum allowable substitution, or nosubstitution; wherein R⁵, R⁶, R⁷, R¹⁰, and R¹¹ are each independentlyselected from the group consisting of hydrogen, deuterium, halide,alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl,acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, and combinations thereof; and wherein anytwo substituents may be joined or fused together to form a ring.
 33. Theconsumer product of claim 32, wherein the consumer product is selectedfrom the group consisting of a flat panel display, a curved display, acomputer monitor, a medical monitor, a television, a billboard, a lightfor interior or exterior illumination and/or signaling, a heads-updisplay, a fully or partially transparent display, a flexible display, arollable display, a foldable display, a stretchable display, a laserprinter, a telephone, a cell phone, tablet, a phablet, a personaldigital assistant (PDA), a wearable device, a laptop computer, a digitalcamera, a camcorder, a viewfinder, a micro-display that is less than 2inches diagonal, a 3-D display, a virtual reality or augmented realitydisplay, a vehicle, a video walls comprising multiple displays tiledtogether, a theater or stadium screen, and a sign.